AU2012250460A1

AU2012250460A1 - Processes for recovering rare earth elements from various ores

Info

Publication number: AU2012250460A1
Application number: AU2012250460A
Authority: AU
Inventors: Richard Boudreault; Carsten DITTRICH; Joel Fournier; Maria Cristina GARCIA; Heinz Krivanec; Denis PRIMEAU; Raymond SIMONEAU
Original assignee: Orbite Aluminae Inc
Current assignee: Orbite Technologies Inc
Priority date: 2011-05-04
Filing date: 2012-05-03
Publication date: 2013-05-02
Anticipated expiration: 2032-05-03
Also published as: AU2016201013A1; EP3141621A1; WO2012149642A1; JP2014513212A; JP5894262B2; RU2013153535A; BR112013028371A2; US9410227B2; CN103857810A; AU2012250460B2; US20140373683A1; EP2705169A1; EP2705169A4

Abstract

The present disclosure relates to processes for recovering rare earth elements from various materials. The processes can comprise leaching the at least one material with at least one acid so as to obtain a leachate comprising at least one metal ion and at least one rare earth element, and a solid, and separating the leachate from the solid. The processes can also comprise substantially selectively removing at least one of the at least one metal ion from the leachate and optionally obtaining a precipitate. The processes can also comprise substantially selectively removing the at least one rare earth element from the leachate and/or the precipitate.

Description

WO 2012/149642 PCT/CA2012/000419 1 PROCESSES FOR RECOVERING RARE EARTH ELEMENTS FROM VARIOUS ORES CROSS-REFERENCE TO RELATED APPLICATIONS [0001] The present application claims priority on US 61/482,253 filed on May 4, 2011; on US 61/535,435 filed on September 16, 2011 and on PCT/CA2012/000253 filed on March 19, 2012. These documents are hereby incorporated by reference in their entirety. TECHNICAL FIELD [0002] The present disclosure relates to improvements in the field of chemistry applied to the recovery, extraction and/or isolation of rare earth elements (REE). For example, such processes are useful for obtaining rare earth elements from various materials and derivatives thereof such as aluminum-bearing materials and derivatives, zinc-bearing materials and derivatives thereof, copper-bearing materials and derivatives thereof, nickel bearing materials and derivatives thereof, and titanium-bearing materials and derivatives thereof. BACKGROUND OF THE DISCLOSURE [0003] In various technologies, there is an increasing need for rare earth elements. In few countries, efforts to reestablish mining of rare earth elements have been undertaken. In the future, supplies of rare earth elements will considerably depend upon economic viability of the extraction and production processes and technological innovations requiring such rare earth elements. [0004] There is thus a need for providing an alternative to the existing solutions for extracting rare earth elements.

WO 2012/149642 PCT/CA2012/000419 2 SUMMARY OF THE DISCLOSURE [0005] According to one aspect, there is provided a process for recovering at least one rare earth element from at least one material, the process comprising : leaching the at least one material with at least one acid so as to obtain a leachate comprising at least one metal ion, and the at least one rare earth element ; substantially selectively precipitating, extracting and/or isolating the at least one metal ion from the leachate and optionally obtaining a precipitate; and substantially selectively precipitating, extracting and/or isolating the at least one rare earth element from the leachate and/or the precipitate. [0006] According to one aspect, there is provided a process for extracting at least one rare earth element from at least one material, the process comprising : leaching the at least one material with at least one acid so as to obtain a leachate comprising at least one metal ion, and the at least one rare earth element; and selectively precipitating at least one member chosen from the at least one rare earth element, and the at least one metal ion. [0007] According to one aspect, there is provided a process for recovering at least one rare earth element from at least one material, the process comprising : WO 2012/149642 PCT/CA2012/000419 3 leaching the at least one material with at least one acid so as to obtain a leachate comprising at least one metal ion, and at least one rare earth element ; optionally substantially selectively precipitating, extracting and/or isolating the at least one rare earth element from the leachate and/or the precipitate. substantially selectively precipitating, extracting and/or isolating the at least one metal ion from the leachate and optionally obtaining a precipitate; and substantially selectively precipitating, extracting and/or isolating the at least one rare earth element from the leachate and/or the precipitate. [0008] According to another example, there is provided a process for recovering at least one rare earth element from at least one material , the process comprising : leaching the the at least one material with at least one acid so as to obtain a leachate comprising at least one metal ion, the at least one rare earth element, and a solid, and separating the leachate from the solid; substantially selectively removing at least one metal ion from the leachate and optionally obtaining a precipitate; and substantially selectively removing the at least one rare earth element from the leachate and/or the precipitate. [0009] According to another example, there is provided process for recovering at least one rare earth element from at least one material, the process comprising : WO 2012/149642 PCT/CA2012/000419 4 leaching the at least one material with at least one acid so as to obtain a leachate comprising at least one metal ion and the at least one rare earth element, and a solid, and separating the leachate from the solid; and substantially selectively removing at least one member chosen from the at least one rare earth element and the at least one metal ion from the leachate. BRIEF DESCRIPTION OF DRAWINGS [0010] In the following drawings, which represent by way of example only, various embodiments of the disclosure: [0011] Fig. 1 shows a bloc diagram of an example of a process for preparing alumina and various other products including rare earth elements, according to the present disclosure; (0012] Fig. 2 shows a bloc diagram of another example of process for preparing alumina and various other products including rare earth elements, according to the present disclosure; [0013] Fig. 3 shows a bloc diagram of an example of process for extracting rare earth elements according to the present disclosure; and [0014] Figs. 4a and 4b show a bloc diagram of another example of a process for extracting rare earth elements according to the present disclosure. DETAILLED DESCRIPTION OF VARIOUS EMBODIMENTS [0015] Further features and advantages will become more readily apparent from the following description of various embodiments as illustrated by way of examples. [0016] It was found that that the rare earth element(s) recovery can be made, for example, in the processes described in the present disclosure at various stages. Moreover, it was found that such processes can be useful even if the rare earth elements are only found as traces. It was also found that such processes can be particularly useful for extracting rare earth elements WO 2012/149642 PCT/CA2012/000419 5 from a solution that is substantially refined or purified. For example, these processes can be useful since they can be applied to solutions from which several of the main components have been removed They can also be applied to solutions before removal of several of the main components. [0017] The expression "at least one aluminum ion", as used herein refers, for example, to at least one type of aluminum ion chosen from all possible forms of Al ions. For example, the at least one aluminum ion can be Al 3 +. [0018] The expression "at least one iron ion", as used herein refers, for example, to at least one type of iron ion chosen from all possible forms of Fe ions. For example, the at least one iron ion can be Fe 2 +, Fe 3 +, or a mixture thereof. [0019] The expression "at least one zinc ion", as used herein refers, for example, to at least one type of zinc ion chosen from all possible forms of Zn ions. For example, the at least one zinc ion can be Zn 2 + [0020] The expression "at least one copper ion", as used herein refers, for example, to at least one type of copper ion chosen from all possible forms of Cu ions. For example, the at least one copper ion can be Cul' or Cu 2 +, or a mixture thereof. [0021] The expression "at least one nickel ion", as used herein refers, for example, to at least one type of nickel ion chosen from all possible forms of Ni ions. For example, the at least one nickel ion can be Ni 2 + or Ni 3 +, or a mixture thereof. [0022] The expression "at least one titanium ion", as used herein refers, for example, to at least one type of titanium ion chosen from all possible forms of Ti ions. For example, the at least one titanium ion can be Ti 3 + or Ti 4 *, or a mixture thereof. [0023] The expression "at least one rare earth element", as used herein refers, for example, to at least one type of rare earth element chosen from all WO 2012/149642 PCT/CA2012/000419 6 the rare earth elements described in the present disclosure in all their possible forms. [0024] The expression "Ga-free solution", as used herein refers, for example, to a solution that comprises about less than 5 %, 2 % or 1 % w/v of gallium. [0025] The expression "Ce-free solution", as used herein refers, for example, to a solution that comprises about less than 5 %, 2 % or 1 % w/v of cerium. [0026] The expression "Sc-free solution", as used herein refers, for example, to a solution that comprises about less than 5 %, 2 % or 1 % w/v of scandium. [0027] The expression "Sm-free solution", as used herein refers, for example, to a solution that comprises about less than 5 %, 2 % or 1 % w/v of samarium. [0028] The expression "Eu-free solution", as used herein refers, for example, to a solution that comprises about less than 5 %, 2 % or 1 % w/v of europium. [0029] The expression "Gd-free solution", as used herein refers, for example, to a solution that comprises about less than 5 %, 2 % or 1 % w/v of gadolinium. [0030] The expression "Y-free solution", as used herein refers, for example, to a solution that comprises about less than 5 %, 2 % or 1 % w/v of yttrium. [0031] The expression "Pr-free solution", as used herein refers, for example, to a solution that comprises about less than 5 %, 2 % or 1 % w/v of praseodymium. [0032] The expression "Nd-free solution", as used herein refers, for example, to a solution that comprises about less than 5 %, 2 % or 1 % w/v of neodymium.

WO 2012/149642 PCT/CA2012/000419 7 [0033] The expression "La-free solution", as used herein refers, for example, to a solution that comprises about less than 5 %, 2 % or 1 % w/v of lanthanum. [0034] The expression "Er-free solution", as used herein refers, for example, to a solution that comprises about less than 5 %, 2 % or 1 % w/v of erbium. [0035] The expression "Dy-free solution", as used herein refers, for example, to a solution that comprises about less than 5 %, 2 % or 1 % w/v of dysprosium. [0036] The expression "rare earth element" as used herein refers, for example, to a rare element chosen from scandium, yttrium, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium, and/or a rare metal chosen from indium, zirconium, lithium, and gallium. These rare earth elements and rare metals can be in various form such as the elemental form (or metallic form), under the form of chlorides, oxides, hydroxides etc. [0037] The expression "the at least one rare earth element" as used herein refers, for example, to a at least one rare element chosen from scandium, yttrium, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium, and/or to at least one rare metal chosen from indium, zirconium, lithium, and gallium. These rare earth elements and rare metals can be in various form such as the elemental form (or metallic form),or under the form of chlorides, oxides, hydroxides etc. [0038] In the processes of the present disclosure, after the leaching, the substantially selectively removing of the at least one member chosen from the at least one rare earth element and the at least one metal from the leachate can be made in various manners. The at least one metal ion (or a second metal ion) can be removed and then, a first metal ion can be removed and finally, the at least one rare earth element can be removed. Alternatively, the WO 2012/149642 PCT/CA2012/000419 8 first metal ion can be removed, then the second metal ion can be removed and finally, the at least one rare earth element can be removed. According to another example, the at least one rare earth element can be removed, then, the first metal ion can be removed, and finally the second metal ion can be removed. Also, the at least one rare earth element can be removed, then, the second metal ion can be removed, and finally the first metal ion can be removed. Various other possible combinations can also be envisaged. [0039] The at least one acid used for leaching the at least one material can be HCI, H 2

SO

4 , HNO 3 or mixtures thereof. More than one acid can be used as a mixture or separately. Solutions made with these acids can be used at various concentration. For example, concentrated solutions can be used. For example, 6 M or 12 M HCI can be used. For example, up to 98 % or 100 % wt H 2

SO

4 can be used. [0040] For example, the at least one material can be leached with HCI having a concentration of about 15 to about 45 weight %, of about 20 to about 45 weight %, of about 25 to about 45 weight %, of about 26 to about 42 weight %, of about 28 to about 40 weight %, of about 30 to about 38 weight %, or between 25 and 36 weight %. [0041] For example, the at least one material can be leached at a temperature of about 125 to about 225 0C, about 150 to about 200 OC, about 160 to about 180 C, or about 165 to about 170 C. [0042] For example, the leaching can be carried out under pressure. For example, the pressure can be about 100 to about 300 or about 150 to about 200 psig. The leaching can be carried out for about 30 minutes to about 5 hours. For example, the leaching can be carried out at a temperature of about 60 0C to about 200 *C. [0043] For example, the leaching can be carried out under pressure into an autoclave. For example, it can be carried out at a pressure of 5 KPag to about 850 KPag, 50 KPag to about 800 KPag, 100 KPag to about 750 KPag, 150 KPag to about 700 KPag, 200 KPag to about 600 KPag, or 250 KPag to about 500 KPag.

WO 2012/149642 PCT/CA2012/000419 9 [0044] For example, the leaching can be carried out at a temperature of at least 80 0C, at least 90 0, or about 100 0C to about 110 *C. In certain cases it can be done at higher temperatures so as to increase extraction yields of rare earth elements in certain ores. For example, the leaching can be carried out at a temperature of at least 100 0C, at least 120 0C, at least 130 0C, at least 140 OC, or about 140 0C to about 175 *C. [0045] For example, in the leachate, the at least one rare earth element can be in the form of an ion. [0046] For example, after the leaching, the at least one rare earth element can be solubilized into the solution and can be found as a soluble ion, associated to chlorine, a sulfate, a nitrate, or hydrates thereof. etc. [0047] For example, after the leaching, (if required) various bases can be used for raising up the pH such as KOH, NaOH, Ca(OH) 2 , CaO, MgO, Mg(OH) 2 , CaC0 3 , Na 2

CO

3 , NaHCO 3 , C02, or mixtures thereof. [0048] For example, the -at least one material can be chosen from aluminum-bearing materials and derivatives, zinc-bearing materials and derivatives thereof, copper-bearing materials and derivatives thereof, nickel bearing materials and derivatives thereof, and titanium-bearing materials and derivatives thereof. [0049] For example, the at least one metal ion can comprise at least one aluminum ion, at least one zinc ion, at least one copper ion, at least one nickel ion, at least one titanium ion and/or at least one iron ion. [0050] For example, the at least one metal ion can comprise a first metal ion and a second metal ion. [0051] For example, the first metal ion can comprise at least one aluminum ion, at least one zinc ion, at least one copper ion, at least one nickel ion, at least one titanium ion and/or at least one iron ion. [0052] For example, the second metal ion can comprise at least one aluminum ion, at least one zinc ion, at least one copper ion, at least one nickel ion, at least one titanium ion and/or at least one iron ion.

WO 2012/149642 PCT/CA2012/000419 10 [0053] For example, the first metal ion can be at least one aluminum ion. [0054] For example, the second metal ion can be at least one iron ion. [0055] For example, the at least one iron ion can be precipitated. When precipitating the at least one iron ion, it can be precipitated by means of an ionic precipitation and it can precipitate in the form of various salts, hydroxides, chlorides or hydrates thereof. For example, the at least one iron ion can be precipitated as FeC 2 , FeCl 3 , Fe(OH) 3 , Fe(OH) 2 , hematite, geotite, jarosite or hydrates thereof. [0056] For example, after the precipitation of the at least one iron ion, the at least one rare earth element can be solubilized into the solution and can be found as a soluble ion, associated as an hydroxide or a salt, or hydrates thereof. [0057] For example, the at least aluminum ion can be precipitated. When precipitating the at least aluminum ion, it can be precipitated by means of an ionic precipitation and it can precipitate in the form of various salts, (such as chlorides, sulfates) or hydroxides or hydrates thereof. For example, the at least one aluminum ion can be precipitated as AI(OH) 3 , AIC1 3 , A1 2

(SO

4

)

3 , or hydrates thereof. [0058] For example, after the precipitation of the at least one metal ion, the at least one rare earth element can be solubilized into the solution and can be found as a an ion associated to an hydroxide or a salt or hydrates thereof. [0059] For example, after precipitation of the at least one metal ion, the residual and substantially purified or refined solution can contain the at least one rare earth element into a mixture of residual soluble ions, such as CE, S0 4 2 , Na+. [0060] The processes of the present disclosure can be effective for treating various materials. The at least one material can be an aluminum-bearing material, The aluminum-bearing metarial can be an aluminum-bearing ore. For example, clays, argillite, mudstone, beryl, cryolite, garnet, spinel, bauxite, WO 2012/149642 PCT/CA2012/000419 11 or mixtures thereof can be used as starting material. The aluminum-bearing material can also be a recycled industrial aluminum-bearing material such as slag. The aluminum-bearing material can also be red mud. [0061] The processes of the present disclosure can be effective for treating various nickel-bearing ores. For example, niccolite, kamacite, taenite, limonite, garnierite, laterite, pentlandite, or mixtures thereof can be used. [0062] The processes of the present disclosure can be effective for treating various zinc-bearing ores. For example, smithsonite, warikahnite, sphalerite, or mixtures thereof can be used. [0063] The processes of the present disclosure can be effective for treating various copper-bearing ores. For example, copper-bearing oxide ores, can be used. For example, chalcopyrite, chalcocite, covellite, bornite, tetrahedrite, malachite, azurite, cuprite, chrysocolla, or mixtures thereof can also be used. [0064] The processes of the present disclosure can be effective for treating various titanium-bearing ores. For example, ecandrewsite, geikielite, pyrophanite, ilmenite, or mixtures thereof can be used. [0065] [0066] For example, the at least one rare earth element can be chosen from scandium, yttrium, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium, and from at least one rare metal chosen from indium, zirconium, lithium, and gallium. [0067] For example, rare earth elements can sometimes be divided into two categories, light rare earth elements (LRE) and heavy rare earth elements (HRE). The light rare earth elements can comprise lanthanum, cerium, praseodymium, neodymium, and samarium (atomic numbers 57-62), and they are usually more abundant than heavy ones. [0068] For example, the at least one rare element can be extracted under the form of various salts, oxides, hydroxides, and hydrates thereof.

WO 2012/149642 PCT/CA2012/000419 12 [0069] For example, the at least one rare earth element can be chosen from scandium, gallium, yttrium, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, dysprosium, erbium, ytterbium and mixtures thereof. [0070] For example, the at least one rare earth element is chosen from scandium, gallium, yttrium, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, dysprosium and mixtures thereof. [0071] For example, the at least one rare earth element is chosen from scandium, gallium, yttrium, cerium and mixtures thereof. [0072] For example, the at least one rare earth element can be yttrium. [0073] For example, the at least one rare earth element can be scandium. [0074] For example, the at least one rare earth element can be gallium. [0075] For example, the at least one rare earth element can be cerium. [0076] For example, the processes can comprise: leaching the at least one material with HCI so as to obtain the leachate comprising the at least one metal ion, and the at least one rare earth element, and the solid and separating the leachate from the solid; substantially selectively removing the at least one metal ion from the leachate, thereby obtaining a composition comprising the metal ion, and the at least one rare earth element; and substantially selectively at least partially removing the at least one metal ion from the composition, thereby obtaining a liquor comprising the at least one rare earth element. [0077] For example, the at least one metal ion can be substantially selectively removed from the leachate by substantially selectively precipitating WO 2012/149642 PCT/CA2012/000419 13 it from the leachate and removing it therefrom by carrying out a solid-liquid separation. [0078] For example, the at least one metal ion can be substantially selectively removed from the leachate by substantially selectively precipitating it under the form of AIC1 3 and removing it therefrom by carrying out a solid liquid separation. [0079] For example, the composition can comprise HCI, the at least one metal ion, and the at least one rare earth element. [0080] For example, the composition can be an acidic composition that comprises, the at least one metal ion, and the at least one rare earth element. [0081] For example, the at least one iron ion can be substantially selectively removed from the composition by carrying out an hydrolysis so as to convert the at least one iron ion into Fe 2

O

3 and removing the precipitated Fe 2 0 3 from the composition by carrying out a solid-liquid separation, thereby obtaining the liquor comprising the at least one rare earth element. [0082] For example, after the removal of the precipitated Fe 2 0 3 , the liquor containing the at least one rare earth element is recirculated back for being further concentrated by being used in precipitating the at least one aluminum ion. [0083] For example, after the removal of the precipitated Fe 2 0 3 , the liquor containing the at least one rare earth element is recirculated back for being further concentrated by being used in precipitating the at least one aluminum ion under the form of AICI 3 . [0084] For example, the at least one iron ion can be Fe 3 + and it can be substantially selectively partially removed from the composition, and wherein the composition can be further treated with a reducing agent so as to convert Fe 3 + into Fe 2 + and then, Fe 2 +, under the form of FeCl 2 , can be removed from the composition by carrying out a solid-liquid separation, thereby obtaining the liquor comprising the at least one rare earth element.

WO 2012/149642 PCT/CA2012/000419 14 [0085] For example, the at least one rare earth element can be substantially selectively precipitated, extracted and/or isolated from the liquor by means of a liquid-liquid extraction. [0086] For example, the at least one rare earth element can be extracted from the liquor by means of liquid-liquid extraction. [0087] For example, the at least one rare earth element can be recovered from the liquor by means of liquid-liquid extraction. [0088] For example, the at least one extracting agent can be chosen from di-(2-ethylhexyl) phosphoric acid (HDEHP), mono(2-ethylhexyl)2-ethylhexyl phosphonate (HEH/EHP), bis(2,4,4-trimethylpentyl)monothiophosphinic acid), octyl phenyl phosphate (OPAP), 2-ethylhexylphosphonic acid mono-2 ethylhexyl ester (PC88A) and optionally toluene, tributyl phosphate, di isoamylmethyl phosphonate, 7-(4-ethyl-1-methyloctyl)-8-hydroxyquinoline, di (2-ethylhexyl) phosphinic acid, bis(2,4,4-trimethylpentyl) phosphinic acid, 8 hydroxyquinoline, and (2-ethylhexyl)phosphonic acid, and mixtures thereof. [0089] For example, the at least one extracting agent can be di-(2 ethylhexyl) phosphoric acid. [0090] For example, the at least one extracting agent can be 2 ethylhexylphosphonic acid mono-2-ethylhexyl ester. [0091] For example, the at least one extracting agent can be octyl phenyl phosphate. [0092] For example, the at least one extracting agent can be tributyl phosphate. [0093] For example, the at least one extracting agent can be chosen from diethylenetriamine-penthaacetic acid (DTPA), ethylenediaminetetraacetic (EDTA), 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA), bis(2,4,4-trimethylpentyl)monothiophosphinic acid and mixtures thereof. [0094] According to one example, when substantially selectively precipitating, extracting and/or isolating the at least one rare earth element WO 2012/149642 PCT/CA2012/000419 15 from the leachate and/or the precipitate, the at least one rare earth element found as an ion in the leachate can be precipitated. [0095] For example, scandium can be precipitated in the form of Sc(OH) 3 , ScCI 3 , ScF 3 , and/or [ScF 6 ]3-(cation), wherein the cation can be sodium, potassium, magnesium, calcium etc [0096] Scandium can be precipitated at a pH of about 7 to about 9, or about 7 to about 8. [0097] For example, the leaching can be carried out at a pH of about 0.5 to about 2.5., about 0.5 to about 1.5, or about 1; then the second metal ion can be precipitated at a pH of at least about 9.5, 10, 10.5, 11, or 11.5; and then the first metal ion can be precipitated at a pH of about 8 to about 9. [0098] For example, the second metal ion can be precipitated at a pH of about 10 to about 12.5, 10.5 to about 11.5, about 10.8 to about 11.2, about 11.5 to about 12.5, or between 10 and 11. [0099] For example, the precipitation of the first metal ion can be carried out at a pH of about 7 to about 11, about 8 to about 10.5, about 8.5 to 10 or about 9 to about 10. [00100] For example, the precipitation of the second metal ion can be carried out at a pH of about 3 to about 6, about 3.0 to about 5.5, about 3 to about 5, about 3 to about 4, about 3.0 to about 3.5, about 3.5 to about 4.0, about 4.0 to about 5.0, about 4.0 to about 4.5, or about 4.5 to about 5.0. [00101] For example, the precipitation of the first metal ion can be carried out at a pH of about 5 to about 6, about 5.0 to about 5.5, or about 5.5 to about 6.0. [00102] For example, when precipitating AICl 3 , highly concentrated dry gaseous HCI at about 90 to about 98 % can be bubbled into the composition comprising the at least one iron ion, the at least one aluminum ion and the at least one rare earth element.

WO 2012/149642 PCT/CA2012/000419 16 [00103] For example, when carrying out the hydrolysis of the at least one iron ion so as to convert the at least one iron ion into Fe 2 0 3 and removing the Fe 2 0 3 , the pH during the hydrolysis can be about below 2.5, 2.0, 1.5 or 1.0. [00104] According to another example, the liquor can comprise the at least one rare earth element under the form of a chloride, and wherein the liquor can be reacted with an extracting agent in order to substantially selectively extract gallium therefrom, thereby obtaining a Ga-free solution and an extracted gallium solution, and separating the solutions from one another. For example, gallium in the liquor can be under the form of GaCl 3 . For example, the extracting agent can be octyl phenyl phosphate, 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester and toluene, tri-butyl phosphate or mixtures thereof. For example, the extracted GaCl 3 can then be precipitated and then converted into Ga 2

O

3 . [00105] For example, the Ga-free solution can then be reacted with another an extracting agent in order to substantially selectively extract cerium therefrom, thereby obtaining a Ce-free solution and an extracted cerium solution, and separating the solutions from one another. For example, the cerium in the Ga-free solution can be under the form of CeCl 3 . For example, the another extracting agent can be tri-butyl phosphate, di-isoamylmethyl phosphonate, di-(2-ethylhexyl) phosphoric acid, 7-(4-ethyl-1-methyloctyl)-8 hydroxyquinoline or mixtures thereof. For example, the process can further comprise converting the extracted cerium into CeO 2 . [00106] For example, the process can further comprise reacting the Ce-free solution with a further extracting agent in order to substantially selectively extract scandium therefrom, thereby obtaining a Sc-free solution and an extracted scandium solution, and separating the solutions from one another. For example, scandium in the Ce-free solution can be under the form of ScCl 3 . For example, the further extracting agent can be di-(2-ethylhexyl) phosphoric acid, di-(2-ethylhexyl) phosphinic acid or a mixture thereof. For example, the process can further comprise converting the extracted scandium WO 2012/149642 PCT/CA2012/000419 17 into Sc 2 0 3 . For example the extracted scandium can be converted into Sc 2 O3 by means of NaOH. [00107] For example, the process can further comprise reacting the Sc-free solution with still a further extracting agent in order to substantially selectively extract samarium, europium or a mixture thereof, thereby obtaining a Sm-free solution and/or Eu-free solution and extracted samarium and/or europium solution, and separating the solutions from one another. For example, the still a further extracting agent can be chosen from bis(2,4,4-trimethylpentyl) phosphinic acid, di-(2-ethylhexyl) phosphoric acid and a mixture thereof. [00108] For example, the process can further comprise reacting the Sm-free solution and/or Eu-free solution with still another extracting agent in order to substantially selectively extract gadolinium, thereby obtaining a Gd-free solution and an extracted gadolinium solution, and separating the solutions from one another. For example, the still another extracting agent can be 8 hydroxyquinoline. [00109] For example, the process can further comprise reacting the Gd-free solution with yet another extracting agent in order to substantially selectively extract yttrium, thereby obtaining a Y-free solution and an extracted yttrium solution, and separating the solutions from one another. For example, the yet another extracting agent can be (2-ethylhexyl)phosphonic acid, di-(2 ethylhexyl)phosphonic acid or a mixture thereof. [00110] For example, the process can further comprise reacting the Y-free solution with still yet another extracting agent in order to substantially selectively extract dysprosium and/or erbium, thereby obtaining a Dy-free solution and/or an Er-free solution and an extracted dysprosium and/or erbium solution, and separating the solutions from one another. [00111] According to another example, the liquor can be reacted with a first extracting agent in order to substantially selectively extract gallium therefrom, thereby obtaining a Ga-free solution and an extracted gallium solution, and separating the solutions from one another.

WO 2012/149642 PCT/CA2012/000419 18 [00112] For example, gallium in the liquor can be under the form of GaCl 3 . For example, the first extracting agent can be tri-butyl phosphate optionally in kerosene. [00113] For example, the Ga-free solution can be reacted with a precipitating agent for precipitating at least one rare earth element present in the Ga-free solution, thereby obtaining a precipitate containing the at least one rare earth element and recovering the precipitate via a solid-liquid separation. [00114] For example, the process can further comprise leaching the precipitate with at least one acid so as to obtain a leach solution comprising the at least one rare earth element. For example the acid can be HCI. For example, the leach solution can be reacted with a second extracting agent so as to substantially selectively extract a first group of rare earth elements, thereby obtaining a solution comprising the extracted rare earth elements of the first group and a raffinate comprising a second group of rare earth elements, and separating the solution from the raffinate. For example, the first group can comprise yttrium and scandium. For example, the second group can comprise cerium, neodynium, europium and praseodymium. For example, the second extracting agent can be chosen from di-(2-ethylhexyl)phosphoric acid and 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester. [00115] For example, the process can further comprise reacting the solution comprising the extracted rare earth elements of the first group with HCI at least once so as to remove impurities therefrom. [00116] For example, the process can further comprise stripping the solution comprising the extracted rare earth elements of the first group with at least one acid so as to obtain a first group strip liquor. For example, the at least one acid can be HCI. [00117] For example, the process can further comprise repeating at least once the extraction with the second extracting agent. [00118] For example, the first group strip liquor can be reacted with a third extracting agent so as to substantially selectively extracting at least one of WO 2012/149642 PCT/CA2012/000419 19 scandium, erbium and dysprosium from the first group strip liquor, thereby obtaining a solution comprising the extracted at least one of scandium, erbium and dysprosium, and an yttrium raffinate, and separating the solution from the raffinate. For example, the third extracting agent can be tri-butyl phosphate. [00119] For example, the process can further comprise stripping the solution comprising the extracted at least one of scandium, erbium and dysprosium solution with at least one acid so as to obtain another first group strip liquor. For example, the at least one acid can be HCI. [00120] For example, the another first group strip liquor can be reacted with a fourth extracting agent so as to substantially selectively extracting erbium and dysprosium from the another first group strip liquor, thereby obtaining a solution comprising the extracted erbium and dysprosium, and a scandium raffinate, and separating the solution from the raffinate. [00121] For example, the another first group strip liquor can be reacted with a fourth extracting agent so as to substantially selectively extracting scandium from the another first group strip liquor, thereby obtaining a solution comprising the extracted scandium, and raffinate comprising erbium dand dysprosium, and separating the solution from the raffinate. [00122] For example, the at least one rare earth element can be substantially selectively precipitated, extracted and/or isolated by means of an adsorption on activated charcoal optionally modified with tributyl phosphate or on a polyurethane polyether foam (PUF). [00123] For example, the at least one rare earth element can be substantially selectively removed by means of a liquid-liquid extraction. For example, the liquid-liquid extraction can be carried out by using an extracting agent. [00124] For example, the process can comprise selectively precipitating at least two members chosen from the at least one rare earth element that is in the form of ions, the second metal ion and the first metal ion. For example, each of the members can be precipitated separately or together.

WO 2012/149642 PCT/CA2012/000419 20 [00125] According to another example, the processes can comprise: leaching the at least one material with HCI so as to obtain the leachate comprising a first metal ion a second metal ion and the at least one rare earth element, and the solid and separating the leachate from the solid; substantially selectively removing the second metal ion from the leachate, thereby obtaining a composition comprising the first metal ion, and the at least one rare earth element; and substantially selectively at least partially removing the first metal ion from the composition, thereby obtaining a liquor comprising the at least one rare earth element. [00126] According to another example, the processes can comprise: leaching the at least one material with HCI so as to obtain the leachate comprising a first metal ion, a second metal ion, and the at least one rare earth element, and the solid and separating the leachate from the solid; substantially selectively removing the second metal ion from the leachate, thereby obtaining a composition comprising the first metal ion, and the at least one rare earth element; and substantially selectively at least partially removing the first metal ion from the composition, thereby obtaining a liquor comprising the at least one rare earth element. [00127] According to another example, the leaching can be carried out at a pH of about 0.5 to about 2.5, then the second metal ion can be precipitated at a pH of at least about 9.5, then the first metal ion can be precipitated at a pH of about 8 to about 9, and then at least one scandium ion can be precipitated at a pH of about 7 to about 8.

WO 2012/149642 PCT/CA2012/000419 21 [00128] According to another example, the leaching can be carried out at a pH of about 0.5 to about 1.5, then the second metal ion can be precipitated at a pH of at least about 10.5, then the first metal ion can be precipitated at a pH of about 8 to about 9, and then at least one scandium ion can be precipitated at a pH of about 7 to about 8. [00129] According to another example, the leaching can be carried out at a pH of about 0.5 to about 1.5, then the second metal ion can be precipitated at a pH of at least about 11, then the first metal ion can be precipitated at a pH of about 8 to about 9, and then at least one scandium ion can be precipitated at a pH of about 7 to about 8. [00130] For example, scandium can be precipitated from a by-product generated during the process. [00131] For example, scandium can be precipitated from a solution generated during the process. For example, scandium can be precipitated using HNO 3 . [00132] For example, the at least one rare earth element can be substantially selectively precipitated, extracted and/or isolated by at least one technique chosen from ion exchange resin, extraction by means of solvent(s) and adsorption. [00133] For example, the at least one rare earth element can be substantially selectively precipitated, extracted and/or isolated by means of an ion exchange resin. [00134] For example, the at least one rare earth element can be substantially selectively precipitated, extracted and/or isolated by means of a liquid-liquid extraction. [00135] For example, the at least one rare earth element can be substantially selectively precipitated, extracted and/or isolated by means of an electrowinning process.

WO 2012/149642 PCT/CA2012/000419 22 [00136] According to another example, the leaching can be carried out at a pH of about 0.5 to about 2.5, then the second metal ion can be precipitated at a pH of at least about 9.5, then the first metal ion can be precipitated at a pH of about 8 to about 9, and then and then the at least one rare earth element can be substantially selectively extracted. [00137] According to another example, the leaching can be carried out at a pH of about 0.5 to about 1.5, then the second metal ion can be precipitated at a pH of at least about 10.5, then the first metal ion can be precipitated at a pH of about 8 to about 9, and then the at least one rare earth element can be substantially selectively extracted. [00138] According to another example, the leaching can be carried out at a pH of about 0.5 to about 1.5, then the second metal ion can be precipitated at a pH of at least about 11, then the first metal ion can be precipitated at a pH of about 8 to about 9, and then the at least one rare earth element can be substantially selectively extracted. [00139] For example, the at least one material / acid ratio can be about 1 / 10 in weight by volume. [00140] According to another example, the processes can further comprise at least one of at least partially removing the second metal ion from the leachate by substantially complexing the second metal ion with an extracting agent; selectively precipitating the second metal ion; selectively precipitating the first metal ion; and WO 2012/149642 PCT/CA2012/000419 23 at least partially removing the first metal ion from the leachate by substantially complexing the first metal ion with another extracting agent. [00141] According to another example, the processes comprise: leaching the at least one material with HCI so as to obtain a leachate comprising a first metal ion and a second metal ion and a solid residue, and separating the leachate from the solid residue; at least partially removing the second metal ion from the leachate by substantially selectively precipitating the second metal ion by reacting the leachate with a base so as to obtain an aqueous composition rich in the first metal ion and comprising the at least one rare element and a precipitate, and removing the precipitate from the composition; purifying the aqueous composition by substantially selectively precipitating the first metal ion, thereby obtaining another composition comprising the at least one rare element and another precipitate, removing the precipitate from the composition; and substantially selectively extracting the at least one rare element from the another composition. [00142] According to another example, the processes can comprise: leaching the at least one material with HCI so as to obtain a leachate comprising a first metal ion and a second metal ion and a solid residue, and separating the leachate from the solid residue, at least partially removing the second metal ion from the leachate by substantially selectively precipitating the second metal ion by reacting the leachate with a base so as to obtain an aqueous composition rich WO 2012/149642 PCT/CA2012/000419 24 in the first metal ion and comprising the at least one rare element and a precipitate, and removing the precipitate from the composition; substantially selectively extracting the first metal ion from the aqueous composition by means of a hollow fiber membrane, or by a liquid-liquid extraction, and removing the extracted first metal ion, thereby obtaining an aqueous composition depleted in the first metal ion comprising the at least one rare element; and substantially selectively extracting the at least one rare element from the aqueous composition. [00143] According to another example, the processes can comprise: leaching the at least one material with HCI so as to obtain a leachate comprising a first metal ion and a second metal ion and a solid residue, and separating the leachate from the solid residue; at least partially removing the second metal ion from the leachate by substantially selectively complexing the second metal ion with an extracting agent so as to obtain an aqueous composition rich in the first metal ion comprising the at least one rare earth element; purifying the aqueous composition by substantially selectively precipitating the first metal ion, thereby obtaining another composition comprising the at least one rare element and another precipitate, removing the precipitate from the composition; and substantially selectively extracting the at least one rare element from the another composition. [00144] According to another example, the processes can comprise: WO 2012/149642 PCT/CA2012/000419 25 leaching the at least one material with HCI so as to obtain a leachate comprising a first metal ion and a second metal ion and a solid residue, and separating the leachate from the solid residue; at least partially removing the second metal ion from the leachate by substantially selectively complexing the second metal ion with an extracting agent so as to obtain an aqueous composition rich in the first metal ion comprising the at least one rare earth element; substantially selectively extracting the first metal ion from the aqueous composition by means of a hollow fiber membrane, or by a liquid-liquid extraction, and removing the extracted first metal ion, thereby obtaining an aqueous composition depleted in the first metal ion comprising the at least one rare element; and substantially selectively extracting the at least one rare element from the aqueous composition depleted in the first metal ion. [00145] According to another example, the processes can comprise: leaching the at least one material with HCI so as to obtain a leachate comprising a first metal ion and a second metal ion and a solid residue, and separating the leachate from the solid residue; at least partially removing the first metal ion from the leachate by substantially selectively precipitating the first metal ion so as to obtain an aqueous composition rich in the second metal ion comprising the at least one rare element and a precipitate, and removing the precipitate from the composition; substantially selectively precipitating the second metal ion from the aqueous composition rich in the second metal ion, and removing the precipitate therefrom, thereby obtaining thereby obtaining an aqueous WO 2012/149642 PCT/CA2012/000419 26 composition depleted in the second metal ion and comprising the at least one rare element; and substantially selectively extracting the at least one rare element from the aqueous composition depleted in the second metal ion. [00146] For example, the first metal ion can comprises at least one aluminum ion. [00147] For example, the second metal ion can comprise at least one iron ion. [00148] For example, the at least one aluminum ion can be precipitated under the form of AIC1 3 in a crystallizer, for example, by sparging gaseous HCI. [00149] For example, the at least one iron ion can be precipitated under the form of Fe 2 0 3 by means, for example, of an hydrolysis. [00150] For example, the aqueous composition rich in the first metal ion can be purified by complexing the first metal ion with an extracting agent so as to obtain a complex, separating the complex form the composition and precipitating the first metal ion. [00151] For example, the aqueous composition rich in the first metal ion can be purified by complexing impurities contained in aqueous composition rich in the first metal ion with an extracting agent, at least partially removing the complexed impurities from the composition and precipitating the first metal ion. [00152] According to another example the processes can comprise: 1- leaching argillite with at least one acid (for example a solution of HCI or gaseous HCI (for example at pH of about 0.5 to about 1.5 or about 0.8 to about 1.2). The leaching cal also be carried out under pressure ; WO 2012/149642 PCT/CA2012/000419 27 2- removing iron by ionic precipitation by raising th at pH of about 10 to about 12 or about 11 to about 12 (or extracting it with extracting agents) and filtering out all non-soluble hydroxides; 3- precipitating aluminum at a pH of about 7.5 to about 9.0 or about 7.8 to about 8.2 and and filtering aluminium hydroxide as a solid; 4- optionally purifying aluminum (AI(OH) 3 ) using at least one of a liquid liquid extraction, a membrane and an extracting agent suitable for complexing aluminum ions; and 5- precipitating, extracting and/or isolating at least one rare earth element can be carried out after at least one of steps 1, 2, 3 and 4. [00153] For more details and explanations regarding at least certain portions of steps 1 to 4, W02008141423, which is hereby incorporated by reference in its entirety, can be referred to. [00154] According to another example the processes can comprise: 1- leaching argillite with an acid (for example a solution of HCI 18 32wt%. The leaching can also be carried out under pressure such as about 350 KPag to about 500 KPag during about 4 to about 7 hours ; 2- removing iron by ionic precipitation by raising the at pH of about 10 to about 12 or about 11 to about 12 (or extracting it with extracting agents) and filtering out all non-soluble hydroxides; 3- precipitating aluminum at a pH of about 7.5 to about 9.0 or about 7.8 to about 8.2 and and filtering aluminium hydroxide as a solid; 4- optionally purifying aluminum (AI(OH) 3 ) using at least one of a liquid liquid extraction, a membrane and an extracting agent suitable for complexing aluminum ions; and 5- precipitating, extracting and/or isolating at least one rare earth element can be carried out after at least one of steps 1, 2, 3 and 4.

WO 2012/149642 PCT/CA2012/000419 28 [00155] According to another example as shown in Fig. 1, the processes can involve the following steps (the reference numbers in Fig. 1 correspond to the following steps) : 1- The aluminum-bearing material is reduced to an average particle size of about 50 to about 80 pm. 2- The reduced and classified material is treated with hydrochloric acid which allows for dissolving, under a predetermined temperature and pressure, the aluminum with other elements like iron, magnesium and other metals including rare earth. The silica remains totally undissolved. 3- The mother liquor from the leaching step then undergoes a separation, a cleaning stage in order to separate the purified silica from the metal chloride in solution. 4- The spent acid (leachate) obtained from step 1 is then brought up in concentration with dry and highly concentrated gaseous hydrogen chloride by sparging this one into a crystallizer. This results into the crystallization of aluminum chloride hexahydrate (precipitate) with a minimum of other impurities. Depending on the concentration of iron chloride at this stage, further crystallization step(s) can be required. The precipitate is then separated from the liquid. 5- The aluminum chloride hexahydrate is then calcined (for example by means of a rotary kiln, fluid bed, etc) at high temperature in order to obtain the desired alumina. Highly concentrated gaseous hydrogen chloride is then recovered and excess is brought in aqueous form to the highest concentration possible so as to be used (recycled) in the acid leaching step. 6- Iron chloride (the liquid obtained from step 4) is then pre concentrated and hydrolyzed at low temperature in view of the Fe 2 03 (hematite form) extraction and acid recovery from its hydrolysis. All heat recovery from the calcination step (step 5), the leaching part exothermic WO 2012/149642 PCT/CA2012/000419 29 reaction (step 1) and other section of the process is being recovered into the pre-concentrator. 10- After the removal of hematite, a solution rich in rare earth elemants can be processed by using any one of the processes described in the present disclosure for recovering rare earth elements from aluminum bearing materials. For example, the recovered rare earth elements can be in various forms such oxides, chlorides, hydroxides etc. As previously indicated in the present disclosure, the expression "rare earth element" can also encompass "rare metal" and thus, in step 10, rare metals can also be recovered. For example, rare metals can be under the form of rare metals oxides. Thus, in Figs. 1 and 2, the step 10 can be, for example, the processes shown in Fig. 3 or in Figs. 4a and 4b. Other non-hydrolyzable metal chlorides (Me-Cl) such as MgC 2 and others then undergo the following steps: 7- The solution rich in magnesium chloride and other non hydrolyzable products at low temperature is then brought up in concentration with dry and highly concentrated gaseous hydrogen chloride by sparging it into a crystallizer. This results into the precipitation of magnesium chloride as an hexahydrate. 8- Magnesium chloride hexahydrate is then calcined (either through a rotary kiln, fluid bed, etc.) and hydrochloric acid at very high concentration is thus regenerated and brought back to the leaching step. 9- Other Me-Cl undergo a standard pyrohydrolysis step where mixed oxides can be produced and hydrochloric acid at the azeotropic point (20.2% wt.) is regenerated. [00156] For example, the liquid can be concentrated to a concentrated liquid having an iron chloride concentration of at least 30% by weight; and then the iron chloride can be hydrolyzed at a temperature of about 155 to about 350 0C while maintaining a ferric chloride concentration at a level of at least 65% by WO 2012/149642 PCT/CA2012/000419 30 weight, to generate a composition comprising a liquid and precipitated hematite, and recovering the hematite. [00157] For example, the liquid can be concentrated to a concentrated liquid having an iron chloride concentration of at least 30% by weight; and then the iron chloride can be hydrolyzed at a temperature of about 155 to about 350 0 C while maintaining a ferric chloride concentration at a level of at least 65% by weight, to generate a composition comprising a liquid and precipitated hematite; recovering the hematite; and recovering rare earths from the liquid. For example, the process can further comprise, after recovery of the rare earths, reacting the liquid with HCI so as to cause precipitation of MgCl 2 , and recovering same. [00158] As previously indicated, various aluminum-bearing materials can be used as starting material of the processes disclosed in the present disclosure. Examples with clays and bauxite have been carried out. However, the person skilled in the art will understand that the continuous processes can handle high percentages of silica (>55%) and impurities as well as relatively low percentages of aluminum (for example as low as about 15%) and still being economically and technically viable. Satisfactory yields can be obtained (>93 95%) on A1 2 0 3 and greater than 75% on rare earth elements. No pre-thermal treatment in most cases are required. The processes disclosed in the present disclosure involve special techniques on leaching and acid recovery at very high strength, thereby offering several advantages over alkaline processes. [00159] In step 1 the mineral, whether or not thermally treated is crushed, milled, dried and classified to have an average particle size of about 50 to about 80 pm. [00160] In step 2, the milled raw material is introduced into the reactor and will undergo the leaching phase. [00161] The leaching hydrochloric acid used in step 2 is a recycled or regenerated acid from steps 5, 6, 8 and 9 and its concentration can vary from 15% to 45% weight. percent. Higher concentration can be obtained using a membrane separation, a cryogenic and/or high pressure approach. The acid WO 2012/149642 PCT/CA2012/000419 31 leaching can be carried out under pressure and at temperature close to its boiling point thus, allowing a minimal digestion time and extended reaction extent (90%-100%). Leaching (step 2) can be accomplished in a semi continuous mode where spent acid with residual free hydrochloric acid is replaced by highly concentrated acid at a certain stage of the reaction or allowing a reduced acid/mineral ratio, thereby reducing reaction time and improving reaction kinetics. For example, kinetic constant k can be : 0.5 0.75 g/mole.L [00162] As previously indicated, alkali metals, iron, magnesium, calcium, potassium, rare earth elements and other elements will also be in a chloride form at different stages. Silica will remain undissolved and will undergo (step 3) a liquid/solid separation and cleaning stage. The processes of the present disclosure tend to recover maximum amount of free hydrochloric acid left and chlorides in solution in order to maximize hydrochloric acid recovery yield, using techniques such as rake classifying, filtration with band filters, centrifugation, and others. Mother liquor free of silica is then named as spent acid (various metal chlorides and water) and goes to the crystallization step (step 4). [00163] In step 4, the spent acid (or leachate) with a substantial amount of aluminum chloride is then saturated with dry and highly concentrated gaseous hydrogen chloride obtained or recycled from step 5, which results in the precipitate of aluminum chloride hexahydrate (AICl 3 * 6H 2 0). The precipitate retained is then washed and filtered or centrifuged before being fed to the calcination stage (step 5). The remaining of the spent acid from step 4 is then processed to acid recovery system (steps 6 to 8) where pure secondary products will be obtained. [00164] In step 5, aluminum oxide (alumina) is directly obtained from high temperature conditions. The highly concentrated hydrogen chloride in gaseous form obtained can be fed to steps 4 and 7 for crystallization. The excess hydrogen chloride is absorbed and used as regenerated acid to the leaching step 2 as highly concentrated acid, higher than the concentration at WO 2012/149642 PCT/CA2012/000419 32 the azeotropic point (>20.2%). For example, such a concentration can be about 25 to about 45 weight % or between 25 and 36 weight %. [00165] After step 4, various chlorides derivatives of (mainly iron chlorides, magnesium chloride and rare earth element in the form of chlorides) are next subjected to an iron extraction step. Such a step can be carried out for example by using the technology disclosed in WO 2009/153321, which is hereby incorporated by reference in its entirety. [00166] In step 6, a hydrolysis at low temperature (155-3500C) is carried out and pure Fe 2

O

3 (hematite) is being produced and hydrochloric acid of at least 15% concentration is being regenerated. The method as described in WO 2009/153321 is processing the solution of ferrous chloride and ferric chloride, possible mixtures thereof, and free hydrochloric acid through a series of steps pre-concentration step, oxidation step where ferrous chloride is oxidized into ferric form, and finally through an hydrolysis step into an operational unit called hydrolyser where the ferric chloride concentration is maintained at 65 weight % to generate a rich gas stream where concentration ensures a hydrogen chloride concentration of 15-20.2% and a pure hematite that will undergo a physical separation step. Latent heat of condensation is recovered to the pre-concentration and used as the heating input with excess heat from the calcination stage (step 5). [00167] The mother liquor left from the hydrolyser (step 6), after iron removal, is rich in other non-hydrolysable elements and mainly comprises magnesium chloride or possible mixture of other elements (various chlorides) and rare earth elements. [00168] Rare earth elements in form of chlorides are highly concentrated in percentage into the hydrolyser operational unit (step 6) and are extracted from the mother liquor (step 10) where the processes defined in the present disclosure for recovering rare earth elements from aluminum-bearing materials can be employed. For example, rare earth elements under various forms can thus be extracted. For example, it can be under the form of oxides. REO. The processes of the present disclosure for recovering rare earth WO 2012/149642 PCT/CA2012/000419 33 elements can allow, for example, to concentrate to a high concentration the following rare earth elements, within the hydrolyser: scandium (Sc), galium (Ga), yttrium (Y), dysperosium (Dy), cerium (Ce), praseodynium (Pr), neodynium (Nd), europium (Eu), samarium (Sm), gadolinium (Gd), lanthanum (La), erbium (Er). Of course, the at least one rare earth element that will be recovered will depend upon the nature of the startin material (aluminum bearing material). [00169] The spent acid liquor from steps 6 and 10 rich in value added metals, mainly magnesium, is processed to step 7. The solution is saturated with dry and highly concentrated gaseous hydrogen chloride from step 5, which results in the precipitation of magnesium chloride hexahydrate. The precipitate retained, is fed to a calcination stage step 8 where pure MgO (>98% wt.) is obtained and highly concentrated hydrochloric acid (for example of at least 38 %) is regenerated and diverted to the leaching step (step 2). An alternative route for step 7 is using dry gaseous hydrochloric acid from step 8. [00170] In step 9, metal chlorides unconverted are processed to a pyrohydrolysis step (700-9000C) to generate mixed oxides and where hydrochloric acid from 15-20.2% wt. concentration can be recovered. [00171] According to another example as shown in Fig. 2, the processes can be similar to the example shown in Fig, 1 but can comprise some variants as below discussed. [00172] In fact, as shown in Fig. 2, the process can comprise (after step 6 or just before step 10) an internal recirculation back to the crystallization step 4. In such a case, The mother liquor from the hydrolyser (step 6) can be recirculated fully or partially to the crystallization of step 4 where a concentration increase will occur with respect to the non-hydrolyzable elements including rare earth elements. [00173] Such a step can be useful for significantly increasing the concentration of rare earth elements, thereby facilitating their extraction in step 10.

WO 2012/149642 PCT/CA2012/000419 34 [00174] With respect to step 7, the solution rich in magnesium chloride and other non-hydrolyzable products at low temperature is, as previously discussed, then brought up in concentration with dry and highly concentrated gaseous hydrogen chloride by sparging it into a crystallizer. This can result into the precipitation of magnesium chloride as an hexahydrate (for example after sodium and potassium chloride removal). [00175] As shown in Fig. 2, an extra step 11 can be added. Sodium chloride can undergo a chemical reaction with sulfuric acid so as to obtain sodium sulfate and regenerate hydrochloric acid at the azeotropic point. Potassium chloride can undergo a chemical reaction with sulfuric acid so as to obtain potassium sulfate and regenerate hydrochloric acid at the azeotropic point. [00176] Certain prophetical examples are hereby provided in the present disclosure for substantially selectively recovering, precipitating, extracting and/or isolating at least one rare earth element. This can be done, for example from the leachate and/or the precipitate and any other downstream derivatives, solutions, precipitates, compositions or liquors. [00177] For example, recovering, precipitating, extracting and/or isolating at least one rare earth element can be carried out by : - precipitating least one rare earth element (for example at a pH of about 6 to about 8, 7 to about 8, or 7 to about 7.5); - using an ion exchange resin (for example, as described in US 4,816,233 (hereby incorporated by reference in its entirety)); - extraction by means of solvent(s) (for example a liquid-liquid extraction can be carried out using di-(2-ethylhexyl) phosphoric acid (HDEHP (also called DEHPA or D2EHPA)), mono(2-ethylhexyl)2 ethylhexyl phosphonate (HEH/EHP), octyl phenyl phosphate (OPAP), 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (PC88A)and optionally toluene (for example as described in Kao et al. in Chemical Engineering Journal, Volume 119, Issues 2-3, June 15, 2006, pages WO 2012/149642 PCT/CA2012/000419 35 167-174 (hereby incorporated by reference in its entirety)) or by means of extracted using an alkyl phosphate (for example as described in US 3,013,859 (hereby incorporated by reference in its entirety)); - using an extracting agent (for example using bis(2,4,4 trimethylpentyl)monothiophosphinic acid or a derivative thereof); - adsorption on activated charcoal (activated carbon adsorption) optionally modified with tributyl phosphate or on a polyurethane polyether foam (PUF); (for example as described in Zhou et al. in RARE METALS, Vol. 27, No. 3, 2008, p223-227 (hereby incorporated by reference in its entirety)) - extraction with hollow fiber membranes; and - using an electrowinning technology (for example as described in US 2004/0042945 (hereby incorporated by reference in its entirety)). [00178] For example, scandium can be precipitated (optionally using HNO 3 ) from a residual solution generated during the process (for example when iron is precipitated and/or when aluminum is precipitated). [00179] For example, when substantially selectively precipitating, extracting and/or isolating at least one rare earth element from the leachate and/or the precipitate and any other downstream derivatives, various sequences can be carried out i.e. depending on the nature of the starting material and the rare earth elements present, a given rare earth element can be more easily extracted before or after another given rare earth element. [00180] For example, as shown in Fig. 3, in a mixture or liquor comprising HCI, water and rare elements in the form of chlorides, the mixture can be treated with an extracting agent in order to extract GaC 3 therefrom, thereby obtaining a Ga-free solution. Such an extracting agent can be, for example, octyl phenyl phosphate (OPAP)or 2-ethylhexylphosphonic acid mono-2- WO 2012/149642 PCT/CA2012/000419 36 ethylhexyl ester (PC88A)and toluene. GaCl 3 can then be precipitated and then converted into Ga 2 0 3 by heating it. [00181] Then, the Ga-free solution can be treated with an extracting agent (for example SME 5 2 9 TM, tri-butyl phosphate or di-isoamylmethyl phosphonate, di-(2-ethylhexyl) phosphoric acid, 7-(4-ethyl-1 -methyloctyl)-8 hydroxyquinoline (Kelex 10 0TM) in n-heptane with the addition of 10% n decanol.) for substantially selectively extracting cerium chloride therefrom so as to obtain a Ce-free solution. CeCl 3 can be eventually converted into CeO 2 . [00182] Then, the Ce-free solution can be treated with an extracting agent such as di-(2-ethylhexyl) phosphoric acid or di-(2-ethylhexyl) phosphinic acid so as substantially selectively extract Sc and to provide a Sc-free solution. The extracted Sc can be treated with an oxidizer (such as NaOH) so as to provide Sc 2 0 3 . [00183] Then, the various remaining rare earth elements (Pr, Nd, Sm, Eu, La, Gd, Y, Dy, Er etc.) in the Sc-free solution can be extracted in different possible orders. [00184] For example, it has to be noted that the process schematized in Fig. 3 can be used as a component of various other processes such as the process schematized in Fig. 1 or in Fig. 2. For example, the step 10 of Figs. 1 and 2 can be the process schematized in Fig. 3. [00185] For example, as shown in Figs. 4a and 4b, a process for extracting rare earth elements can comprise : Ferric reduction to ferrous using iron; Separation of gallium from the ferrous chloride solution; Precipitation and pre-concentration of rare earth elements from the raffinate; Re-leaching and fractioning of the rare earth elements into light (LRE) and heavy (HRE) groups; WO 2012/149642 PCT/CA2012/000419 37 Separation of yttrium from scandium and heavy rare earth elements; and Separation of scandium and heavy rare earth elements [00186] The reduction of ferric to ferrous with a reducing agent (such as metallic iron) can be used so as to prevent iron coextraction or iron precipitation. The reaction time can be very short and it can generate heat. [00187] As shown in Figs. 4a and 4b, The ferric chloride feed solution 101 can be fed to an agitated reaction tank and a reducing agent (for example metallic iron 102 ) can added so as to allow for converting ferric chloride to ferrous chloride (see "Ferric Removal"). After a solid-liquid separation (s/I separation), the resulting filtrate 103 can be further treated in a gallium extraction circuit. A filter cake, containing solid material and iron, can be dewatered and the resulting slurry can then be prepared for disposal. [00188] Gallium can then be extracted with an organic solution containing an extracting agent (for example tri-butyl phosphate (TBP) dissolved in kerosene) (see "Gallium Recovery"). The rare earth and iron can thus be left in the raffinate. The extraction can vary as a function of the chloride ion concentration. For example, the higher chloride ion concentration, the stronger tendency for gallium complex formation and the better extraction. [00189] For example, for gallium (recovery from hydrochloric acid solutions, reagents such as tri-butyl phosphate or tertiary amines (e.g. Alamine 336) can be used. For example, when increasing hydrochloric acid (HCI) concentration, gallium extraction can rise to a maximum and can then decrease again. For example, HCI concentration can be increased up to about 4 M HCI for the gallium extraction. Under these conditions, gallium can be present in the form of HGaCl 4 complex and TBP extracted gallium as a trisolvate (HGaCl 4 *3TBP) (for example when the extracting agent is TBP).

WO 2012/149642 PCT/CA2012/000419 38 [00190] Co-extracted iron, accumulated in the organic phase can be scrubbed with hydrochloric acid (see "Gallium Strip Liquor"). The resulting organic solution, containing gallium can be fed to a stripping circuit where gallium is stripped with water 104. The raffinate 106, containing ferrous chloride and the rare earth elements, can then be fed to the rare earth precipitation section (see "Bulk REE Removal"). The final strip liquor 105 contains gallium. [00191] For example, oxalate precipitation of rare earth elements result in very low solubility of the compounds in aqueous solution. The precipitation of rare earth oxalates can be achieved by addition of a precipitation reagent 107. For example, oxalic acid 107 can be used for the precipitation. For example, precipitating agent that are effective for precipitating rare earth elements of the trivalent (such as oxalate (from oxalic acid)) can be used. For example, such precipitating agents can have provide a very low solubility in aqueous solution to so-formed precipitate. [00192] An overflow from the primary rare earth elements precipitation 109 can be fed to a ferrous treatment circuit. After filtration, the filter cake, containing the rare earth elements, can be fed to a washing and dewatering unit. A resulting slurry 108 can then be prepared for re-leaching (see "REE Re-leaching"). Re-leaching of the rare earth filter cake can be carried out using hydrochloric acid 110. [00193] From a pre-concentrated and pH adjusted chloride solution 111, that contains for example about 150 to about 250 g/L, rare earth elements yttrium, scandium and the heavy rare earth (HRE) are extracted (see "Primary REE Recovery") with an extracting agent (for example (di-(2 ethylhexyl)phosphoric acid (D2EHPA) or 2-ethylhexylphosphonic acid mono 2-ethylhexyl ester (PC88A (also called lonquest m 801) in kerosene)). Scandium, the other HRE and also yttrium can be extracted and leaving the light rare earth elements (LRE) in a raffinate 113.

WO 2012/149642 PCT/CA2012/000419 39 [00194] A loaded organic phase can then be selectively scrubbed with hydrochloric acid (2 M HCI) to remove the co-extracted LRE. A secondary scrubbing section can remove europium by using weak hydrochloric acid (1 to 1.5 M HCI). The extract, containing yttrium, scandium and the HRE, can then be stripped with strong acid (3.5 M HCI) 112. [00195] The HRE strip liquor 114, containing yttrium and scandium, can be treated further to obtain more than 90 % Y 2 0 3 and Sc 2 03 in a first circuit of a double solvent extraction purification process. In a first step, the aqueous solution, containing about 25 g / L (of rare earth elements in the form of oxides) and 0.4 M HCI, can be brought into contact with an extracting agent (for example (di-(2-ethylhexyl)phosphoric acid (D2EHPA) or 2 ethylhexylphosphonic acid mono-2-ethylhexyl ester (PC88A (also called lonquest T M 801) in kerosene)) (see "Secondary REE Recovery"). The loaded organic phase is then scrubbed with diluted hydrochloric acid. Scandium, yttrium and HRE can be extracted by the reagent and finally stripped with strong hydrochloric acid 115 at a high oxide / acid ratio. The final strip liquor would have a concentration in rare earth elements oxides of about 40 g/L and about 1 M HCI. This solution is partially neutralized. [00196] This pre-treated strip liquor 116 can be further extracted with an extracting agent (for example tri-butyl phosphate (TBP) in kerosene). The treatment can be done in a multi stage procedure, and ending up in a final stripping of the loaded organic with water 117. All HRE and scandium can thus extracted, leaving yttrium in a raffinate 119. A final strip liquor 118, containing HRE, forms the source for further separation of scandium and heavy rare earth. In order to do so, various possible extracting agents can be used such as di-(2-ethylhexyl) phosphoric acid. [00197] The separation of scandium from other HRE, (for example dysprosium and erbium) can be carried out using a further solvent extraction purification circuit, similar to the yttrium separation and purification process and previously described. Thus, the extracting agent can be the same or a different one, the strip solution 120 can be the same than 117, thereby WO 2012/149642 PCT/CA2012/000419 40 providing a scandium raffinate 121 and a strip liquor 122 comprising europium and erbium. [00198] As an alternative, yttrium can be extracted as described in US 3,751,553 (hereby incorporated by reference in its entirety). In fact, yttrium can be extracted starting from a xenotime concentrate. It can be done by using three solvent extraction circuits. In a first step, DEHPA can be used to separate yttrium. In a second step, tri (caprylmethyl) ammonium nitrate (Aliquat 336) can be used to extract and separate cerium and leave yttrium in the raffinate. In a third step, Tm, Yb, and Lu can be extracted by means of tri (caprylmethyl) ammonium thio cyanate. In this extraction loop, yttrium behaves like a cerium element. From this step, high-purity of yttrium oxide can be obtained. [00199] According to another alternative, yttrium oxide can be extracted in two steps i.e. tri (caprylmethyl) ammonium nirate can be used to separate a mixture La - ErN - Lu and then, a purification of yttrium is carried out using versatic acid. [00200] Solvent extraction is a selective separation procedure for isolating and concentrating valuable elements from an aqueous solution with the aid of an organic solution. In the procedure the aqueous solution containing the element of interest, often at a low concentration and together with other dissolved substances (pollutants), is mixed (extraction) with an organic solvent containing a reagent. The element of interest reacts with the reagent to form a chemical compound that is more soluble in the organic than in the aqueous solution. As a consequence, the element of interest is transferred to the organic solution. [00201] Subsequently, in order to recover the extracted substance, the organic solution is mixed (stripping) with an aqueous solution whose composition is such that the chemical compound between the element and the reagent is split and, thus, the element is recovered in the "new" aqueous solution, in a pure form. The concentration of the element in the "new" WO 2012/149642 PCT/CA2012/000419 41 aqueous solution may be increased, often to 10-100 times that of the original aqueous solution, through adjustment of the liquid flow rates. Freed from the extracted element, the organic solution is returned for further extraction, either directly or after a fraction of it has been cleansed of impurities. [00202] Important factors that govern this solvent extraction process can be, for example, the number of extraction, scrubbing and stripping stages, organic solvent concentration and diluent. [00203] In a typical solvent extraction process, the aqueous phase, containing the rare earth elements, can be for example a chloric or nitric acidic solution. The organic phase comprises an extracting agent as those recited in the present disclosure or alternatives in an organic solvent such as an aliphatic diluent. [00204] Solvent extraction technique can be used as separation and purification procedure for the rare earth elements. Some of the following properties are particularly relevant when selecting an extracting agent or chemical extractant: High selectivity over other unwanted metals and acids during the extraction process, High transfer capacity on the extractant, Good chemical stability, Fast kinetics. [00205] For example, precipitation denotes the removal of the rare earth elements from solution by the addition of a chemical reagent to form a new, less soluble (solid) compound. For example, a complete precipitation can be carried out by oxalate, hydroxide, or other compounds. [00206] Hydroxide precipitation and double sulphate can also be used. For large scale operation, ammonia can be used for carrying out hydroxide WO 2012/149642 PCT/CA2012/000419 42 precipitation from nitrate or chloride solutions. The double sulphates

RE

2 (SO4) 3 *Na 2

SO

4 *nH 2 0 can be precipitated by either addition of sodium sulphate to the solution containing rare earth elements. The precipitation reaction of trivalent rare earth elements in aqueous solution is according to the following equation:

REE

3 * + 3 H 2 0 -1 REE(OH) 3 + 3 H* [00207] The below presented examples are non-limitative and are used to better exemplify the processes of the present disclosure. Example 1 Preparation of an aluminum-bearing material sample [00208] The aluminum-bearing material (for example argillite) can be finely crushed in order to help along during the following steps. For example, micronization can shorten the reaction time by few hours (about 2 to 3 hours). In order to remove most of the iron, a leaching step at room temperature is optionally carried out between the crushing step and the calcination step. This operation is, for example, carried out with hydrochloric acid HCI (12 M or 32 wt%) and an argillite / acid ratio (weight / volume) of 1:5 is used. Depending on experimental conditions (sizes of the particles, time of treatment, agitation system), about 65 % to about 93 % of the iron can then be dissolved . However, this leaching step can also bring in a certain percentage of the aluminum (0 - 5 %). The last step of the preparation of argillite comprises calcining the pretreated argillite. This can be accomplished at a calcinating temperature greater than 550 0C for a period of about 1 to 2 hours. For example, a heat treatment makes it possible to increase the quantity of extracted aluminum by about 30 % to about 40 % for the same period of time. In others words, the quantity of extracted aluminum is doubled. When leaching at room temperature is carried out, a phase separation before calcination can be made in order to recover the acid and reduce heating costs.

WO 2012/149642 PCT/CA2012/000419 43 Acid leaching [00209] Acid leaching can comprise reacting the crushed and roasted argillite with at least one acid solution (for example HCI) at elevated temperature during a given period of time. For example, the argillite / acid ratio can be of about of 1:10 (weight / volume), the HCI concentration can be of about 6 M or about 18 to 20 wt%, the temperature can be of about 100 0C to about 110 0C, and the reaction time can be of about 30 minutes to about 7 hours. Under such conditions, more than about 90 % of the aluminum and about 100 % of the iron can be extracted in addition to impurities. Alternatively, the leaching can be carried out at a temperature of about 150 0C to about 175 0C at a pressure of about 350 KPag to about 500 KPag during about 4 to about 7 hours. [00210] During the second half of such a treatment (for example the last 2 or 3 hours), a portion of the excess acid can be recovered by flashing and condensation. Once the extraction is terminated, the solid (argillite impoverished in metals) can be separated from the liquid by decantation or by filtration, after which it is washed. The residual leachate and the washing water may be completely evaporated. The corresponding residue can thereafter be counter currently washed many times with water so as to decrease acidity and to lower the quantities of base used (for example, NaOH, KOH, Ca(OH) 2 , Mg(OH) 2 , etc. ) that are required to adjust the pH during iron removal. The acid recovered will can be re-utilized after having adjusted its titer either by adding either gaseous HCI, or by adding concentrated HCI (12 M). After the reaction, the titer of the acid can vary from about 4 M to about 6 M depending on experimental conditions. With respect to the solid, it represents about 65 % to about 75 % of the initial mass of argillite, it can be valorized and be used again either as an ion exchange resin, or as an adsorbent. [00211] Alternatively, the HCI leaching can be carried out under pressure (so to increase the reaction temperature) into an autoclave.

WO 2012/149642 PCT/CA2012/000419 44 [00212] The rare earth element(s) recovery can be made, for example, at this stage, after carrying out the above mentioned acid leaching. Removal of iron [00213] Several alternatives are proposed in the present disclosure for carrying out iron removal. For example, iron removal can be carried out by substantially selectively precipitating iron ions at certain pH values. Alternatively, some extracting agents can be used as described in W02008141423. A membrane can also be used in combination with such extracting agents [00214] For example, removal of iron can be carried out by ionic precipitation of the latter in basic medium for example at a pH of at least 10 or at a pH of about 11.5 to about 12.5. The pH can also be about 3 to about 6, or about 3 to about 5 or about 3 to about 4. Such a step can be made by adding a solution of NaOH, for example at a concentration of 10 M. Other bases such as KOH can also be used. Then, all that is required is to separate the solid portion from the liquid portion by filtration, decantation or centrifugation and to rinse the solid by means of a diluted base, such as a solution of NaOH (for example NaOH at a concentration of 0.01 M to 0.02 M). Then, the solid is washed conter currently with water. The liquid portion comprises aluminum and alkaline-earths A substantially complete removal of the iron and of nearly all the impurities (other metals) can thus be achieved as insoluble and washed hydroxides. Optionally, it is possible to recover iron by using a refining step by liquid-liquid extraction through a hollow fiber membrane. [00215] Alternatively, removal of iron can be carried out by using an extracting agent and a hollow fiber membrane. Various extracting agents that could substantially selectively complex iron ions over aluminum ions (or aluminum ions over iron ions) could be used in such a step depending an Al / Fe ratio. For example, extraction can be carried out by using HDEHP (or DEHPA) di(2-ethylhexyl)phosphoric acid) as an extracting agent adapted to WO 2012/149642 PCT/CA2012/000419 45 complex iron ions. A concentration of about 1 M of HDEHP can be used in an organic solvent, such as heptane or any hydrocarbon solvent. Such an extraction can require relatively short contact times (few minutes). For example, the pH of the order of 2 can be used and aqueous phase / organic phase ratio can be of about 1:1. It was observed that is possible to extract from 86 % to 98 % iron under such conditions. It will be understood that in the present case, iron is trapped in the organic phase. To recover iron in an aqueous phase, a reverse extraction with hydrochloric acid (2 M or 6 M) and organic phase / acidic phase ratio of about 1:0.5 can then be carried out. In such a case, the resulting aqueous phase is rich in Fe 3 ions. [00216] The rare earth element(s) recovery can be made, for example, at this stage, after carrying out the above mentioned iron recovery. [00217] With solvent extraction using countercurrent techniques, hydrochloric acid stripping and then contacting with MgO solution, therefore precipitating the rare earth elements in the form of hydroxide and then converting the products into their corresponding oxide into a calcination device. Aluminum recovery [00218] This step can also be carried in various ways. For example, aluminum ions can be precipitated under the form of AI(OH) 3 (for example an hydrated form of AI(OH) 3 ) at a pH of about 7 to about 9 or about 7.5 to about 8.5 or about 8. Alternatively, the aluminum ions can be reacted with an extracting agent as descried in W02008141423. [00219] The solution obtained from the previous step using either the precipitation or the extraction technique is relatively clean and mainly contains aluminum for example about 90 % to about 95 % or even as high as about 90 % to about 99.8 % (without the alkaline-earths in the case of precipitation). Recovery of the latter can be carried out by liquid-liquid extraction for example by using a same hollow fiber membrane and an extracting agent that is WO 2012/149642 PCT/CA2012/000419 46 adapted to complex at least substantially selectively aluminum over other metals or residues. For example, bis(2,4,4-trimethylpentyl) phosphinic acid (such as the one sold under the name Cyanex T M 272) can be used as an extracting agent specific to aluminum. For example, this extracting agent can be used at a concentration of about 20 % v/v in an organic solvent such as heptane. The ratios between the aqueous phase and the organic phase can be of about 1:1 to about 1:3. For example, the extraction temperatures can be of about 40 0C and the pH can be maintained at about 2.5 to about 3.5. It was observed that such a technique makes it possible to extract more than 70 - 90 % of the aluminum. After the aluminum has been trapped in the organic phase, it can be recovered in the form of a concentrate of A13+ ions by using a back extraction. For example, the reverse extraction can be carried out at a temperature of about 40 *C with hydrochloric acid (for example at a concentration of 6 M). Under this condition, more than 90 % of aluminum can be recovered. [00220] The rare earth element(s) recovery can be made, for example, at this stage, after carrying out the above mentioned aluminum recovery. [00221] Then, A13+ can be converted into aluminum hydroxide (for example an hydrated form of AI(OH) 3 ) by addition of a base such as NaOH. Finally,

AI(OH)

3 can be converted into alumina (alumina A1 2 0 3 ) by r calcinating

AI(OH)

3 for example at a temperature of about 800 0C tol 200 C. [00222] Further purification can be performed by recrystallization. Rare earth elements recovery [00223] Rare earth elements recovery can then be made, for example, at this stage by using any of the technology previously mentioned for doing so. For example, the at least one rare earth element contained in the residual solutions obtained from the above-mentioned process. For example, the at least one rare earth element can be in low concentration for example at a concentration of less than about 50, about 25, 15, 10, 5, 4, 3, 2 or 1 ppm in WO 2012/149642 PCT/CA2012/000419 47 the lixiviate or leachate or a solution obtained during the process .The rare earth elements can be concentrated in the latter stage of the process prior to extraction with solvent(s). It was demonstrated that through an internal concentration loop, concentration can be significantly increased (for example from 100 to 1000 times) thereby providing more effective conditions for substantially selectively precipitating, extracting and/or isolating at least one rare earth element. Example 2 [00224] As a starting material a sample of clay (argillite) was obtained from the Grande Vallee area in Quebec, Canada. [00225] These results represent an average of 80 tests carried out from samples of about 900 kg each. These tests were carried out by a using a process as shown in Fig. 1. [00226] Crude clay in the freshly mined state after grinding and classification had the following composition: A1 2 0 3 : 15% - 26%; SiO 2 : 45% - 50%; Fe 2 03: 8% - 9%; MgO : 1% - 2%; Rare earth elements: 0.04% - 0.07%; LOI : 5% - 10%. [00227] This material is thereafter leached in a two-stage procedure at 140 170 'C with 18-32 weight % HCI. The HCI solution was used in a stoichiometric excess of 10-20% based on the stoichiometric quantity required for the removal of the acid leachable constituents of the clay. In the first leaching stage of the semi-continuous operation (step 2), the clay was contacted for 2.5 hours with required amount or certain proportion of the total WO 2012/149642 PCT/CA2012/000419 48 amount of hydrochloric acid. After removal of the spent acid, the clay was contacted again with a minimum 18 weight % hydrochloric acid solution for about 1.5 hour at same temperature and pressure. [00228] The leachate was filtered and the solid was washed with water and analyzed using conventional analysis techniques (see step 3 of Fig. 1). Purity of obtained silica was of 95.4% and it was free of any chlorides and of HCI. [00229] After the leaching and silica removal, the concentration of the various metal chlorides was: AIC1 3 : 15-20%; FeC1 2 : 4-6%; FeCl 3 : 0.5-2.0%; MgCl 2 : 0.5-2.0 %; Free HCI : 5-50 g/I [00230] Spent acid was then crystallized using about 90 to about 98% pure dry hydrochloric acid in gas phase in two stages with less than 25 ppm iron in the aluminum chloride hexahydrate formed. The concentration of HCI in solution (aqueous phase) was about 25 to about 32 % The recovered crystallized material (hydrate form of AIC1 3 having a minimum purity of 99.8 %) was then calcined at 9300C or 12500C, thus obtaining the a-portion of the alumina. [00231] HCI concentration in gas phase exiting the calcination stage was having a concentration of about 21 to about 32 % by weight and was used (recycled) for crystallization of the AICl 3 and MgCl 2 . Excess of hydrochloric acid is absorbed at the required and targeted concentration for the leaching steps. [00232] Iron chloride (about 90% to about 95% in ferric form) is then sent to a hydrothermal process in view of its extraction as pure hematite (Fe 2 0 3 ). This can be done by using the technology described in WO 2009/153321 of low WO 2012/149642 PCT/CA2012/000419 49 temperature hydrolysis with full heat recovery from calcining, pyrohydrolysis and leaching stage. [00233] Before step 10 (in both processes of Figs. 1 and 2) it was demonstrated that about 90 to about 98 % by weight of the elements (Al, Fe, Mg and rare earths elements such as (Sc, Ga, Y, Ce) found in the starting material were recovered. It can be estimated that the processes for recovering rare earth elements from an aluminum-bearing material disclosed in the present disclosure can be efficient for recovering about 90 % of the rare earth elements. Thus, with respect to the examples of processes provided in Figs. 1 and 2, it can be estimated that the overall yield for recovering the at least one rare earth element from the aluminum-bearing material would be about 80 % to about 90 %. [00234] Rare earth elements can be extracted from the mother liquor of the hydrolyzer (where silica, aluminum, iron and a great portion of water have been removed) following pre-concentration from crystallization to the hydrolyzer. In the form of chlorides the rare earth elements (RECI) are considerably concentrated and ready to be extracted. Rare earth elements have demonstrated to concentrate by a factor 5 to 10 in average within the hydrolyzer itself on a single pass through it (without any concentration loop). The concentration factors obtained within the hydrolyser (single pass) were as follows: Ce: > 6 La: > 9 Nd: > 7 Y: > 9 [00235] The person skilled in the art would thus clearly understand that such a concentration could be considerably more increased when carrying out a concentration loop.

WO 2012/149642 PCT/CA2012/000419 50 [00236] Remaining magnesium chloride is sparged with dry and highly concentrated hydrochloric acid and then calcinated to MgO while recovering acid at its azeotropic point. [00237] Mixed oxides containing other non-hydrolyzable components were then undergoing a pyrohydrolysis reaction at 700-800'C and recovered acid (15-20.2% wt.) was rerouted for example to the leaching system. Overall yields obtained: A1 2 0 3 : 93-95% recovery; Fe 2 03: 98-99.5% recovery; Rare earth elements : 95% minimum recovery (mixture); MgO: 96-98% recovery; Material discarded : 0-5% maximum; HCI global recovery: 99.75% minimum; HCI strength as feed to leaching 15-32%; Red mud production : none. Example 3 [00238] A similar feed material (bauxite instead of clay) was processed as per in example 2 up to the leaching stage and revealed to be easily leachable under the conditions established in example 2. It provided an extraction percentage of 100% for the iron and over 95 % for aluminum. The process was found to be economically viable and no harmful by-products (red mud) were generated. A rare earth elements recovery (as a mixture) of about 90 to about 95 % (by weight as compared to the starting material) was observed Samples tested had various concentrations of A1 2 0 3 (up to 51%), Fe 2 0 3 (up to 27%) and MgO (up to 1.5%).

WO 2012/149642 PCT/CA2012/000419 51 [00239] The processes of the present disclosure provide a plurality of important advantages and distinction over the known processes [00240] The processes of the present disclosure can provide fully continuous and economical solutions that can successfully extract alumina from various type of minerals while providing ultra pure secondary products of high added value including highly concentrated rare earth elements. The technology described in the present disclosure can allow for an innovative amount of total acid recovery and also for a ultra high concentration of recovered acid. When combing it to the fact that combined with a semi continuous leaching approach that favors very high extraction yields and allows a specific method of crystallization of the aluminum chloride and concentration of other value added elements such as rare earth elements. [00241] Specifically through the type of equipment used (for example vertical roller mill) and its specific operation, raw material grinding, drying and classifying can be applicable to various kinds of mineral hardness (furnace slag for example), various types of humidity (up to 30%) and incoming particle sizes. The particle size established provides the advantage, at the leaching stage, of allowing optimal contact between the minerals and the acid and then allowing faster kinetics of reaction. Particles size employed reduces drastically the abrasion issue and allows for the use of a simplified metallurgy/lining when in contact with hydrochloric acid. [00242] A further advantage of the processes of the present disclosure is the combined high temperature and high incoming hydrochloric acid concentration. Combined with a semi continuous operation where the free HCI driving force is used systematically, iron and aluminum extraction yields do respectively reach 100% and 98% in less than about 40 % of the reference time of a basic batch process. Another advantage of higher HCI concentration than the concentration at azeotropic point is the potential of capacity increase. Again a higher HCI concentration than the concentration of HCI at the azeotropic point and the semi-continuous approach represent a substantial advance in the art.

WO 2012/149642 PCT/CA2012/000419 52 [00243] Another advantage in that technique used for the mother liquor separation from the silica after the leaching stage countercurrent wash, is that band filters provide ultra pure silica with expected purity exceeding 98%. [00244] The crystallization of AIC1 3 into AIC1 3 * 6H 2 0 using dried, cleaned and highly concentrated gaseous HCI as the sparging agent allows for a pure aluminum chloride hexahydrate with only few parts per million of iron and other impurities. A minimal number of stages can be required to allow proper crystal growth. [00245] The direct interconnection with the calcination of AIC1 3 0 6H 2 0 into A1 2 0 3 which does produce very high concentration of gas allows the exact adjustment in continuous of the HCI concentration within the crystallizer and thus proper control of the crystal growth and crystallization process. [00246] The applicants have now discovered fully integrated and continuous processes with total hydrochloric acid recovery for the extraction of alumina and other value added products such as rare earth elements from various materials that contain aluminum (clay, bauxite, slag, red mud etc.) containing aluminum. In fact, the processes allows for the production of pure alumina and other value added products purified such as purified silica, pure hematite, pure other minerals (ex: magnesium oxide) and rare earth elements. In addition, the processes do not require thermal pre-treatment before the acid leach operation. Acid leach can be carried out using semi-continuous techniques with high pressure and temperature conditions and very high regenerated hydrochloric acid concentration. [00247] The advantage of the high temperature calcination stage, in addition for allowing to control the a-form of alumina required, is effective for providing a concentration of hydrochloric acid in the aqueous form (>38%) that is higher than the concentration of HCI at the azeotropic point and thus providing a higher incoming HCI concentration to the leaching stage. The calcination stage hydrochloric acid network can be interconnected to two (2) crystallization systems and by pressure regulation excess HCI can be being absorbed at the highest possible aqueous concentration. The advantage of WO 2012/149642 PCT/CA2012/000419 53 having a hexahydrate incoming feed allows for a continuous basis to recover acid at a concentration that is higher than the azeotropic concentration. This HCI balance and double usage into three (3) common parts of the process and over azeotropic point is a substantial advance in the art. [00248] Another advantage is the use of the incoming chemistry (ferric chloride) to the iron oxide and hydrochloric acid recovery unit where all excess heat load from any calcination part, pyrohydrolysis and leaching part is being recovered to preconcentrate the mother liquor in metal chloride, thus allowing, at very low temperature, the hydrolysis of the ferric chloride in the form of very pure hematite and the acid regeneration at the same concentration than at its azeotropic point. [00249] A further major advantage of the instant process at the ferric chloride hydrolysis step is the possibility to concentrate rare earth elements in form of chlorides at very high concentration within the hydrolyser reactor. The advantage is that the processes of the present disclosure benefit from the various steps where gradual concentration ratios are applied. Thus, at this stage, having the silica, the aluminum, the iron and having in equilibrium a solution close to saturation (large amount of water evaporated, no presence of free hydrochloric acid) allows for taking rare earth elements in parts per million into the incoming feed and to concentrate them in high percentage portion directly at the hydrolyser. Purification of the specific oxides of the rare earth elements (REO) can then be performed using known techniques when in percentage levels. The advantage is doubled here: concentration at very high level of rare earth elements using integrated process stages and most importantly the approach prevents from having the main stream (very diluted) of spent acid after the leaching step with the risk of contaminating the main aluminum chloride stream and thus affecting yields in A1 2 0 3 . Another important improvement of the art is that on top of being fully integrated, selective removal of components allows for the concentration of rare earth elements to relatively high concentration (percentages).

WO 2012/149642 PCT/CA2012/000419 54 [00250] Another advantage of the process is again a selective crystallization of MgCl 2 through the sparging from either the alumina calcination step or the magnesium oxide direct calcination where in both cases highly concentrated acid both in gaseous phase or in aqueous form are being generated. As per aluminum chloride specific crystallization, the direct interconnection with the calciner, the HCl gas very high concentration allows for exact adjustment in continuous of the crystallizer based on quality of magnesium oxide targeted. Should this process step (MgO production or other value added metal oxide) be required based on incoming process feed chemistry, the rare earth elements extraction point then be done after this additional step; the advantage being the extra concentration effect applied. [00251] The pyrohydrolysis allows for the final conversion of any remaining chloride and the production of refined oxides that can be used (in case of clay as starting material) as a fertilizer and allowing the processing of large amount of wash water from the processes with the recovery hydrochloric acid in close loop at the azeotropic point for the leaching step. The advantage of this last step is related to the fact that it does totally close the process loop in terms of acid recovery and the insurance that no residues harmful to the environment are being generated while processing any type of raw material, as previously described. [00252] A major contribution to the art is that the proposed fully integrated processes of the present disclosure is really allowing, among others, the processing of bauxite in an economic way while generating no red mud or harmful residues. In addition to the fact of being applicable to other natural of raw materials (any suitable aluminum-bearing material or aluminous ores), the fact of using hydrochloric acid total recovery and a global concentration that is higher than the concentration at the azeotropic point (20% to 38%), the selective extraction of value added secondary products and compliance (while remaining highly competitive on transformation cost) with environmental requirements, represent major advantages in the art.

WO 2012/149642 PCT/CA2012/000419 55 [00253] It was thus demonstrated that the present disclosure provides fully integrated processes for the preparation of pure aluminum oxide using a hydrochloric acid treatment while producing high purity and high quality products (minerals) and recovering rare earth elements. [00254] The person skilled in the art will thus understand that the processes of the present disclosure can be used in combination with various processes for treating aluminum-bearing materials. In fact, various different treatments can be carried out to the aluminum-bearing materials in the processes of the present disclosure including recovery of at least one rare element. [00255] While a description was made with particular reference to the specific embodiments, it will be understood that numerous modifications thereto will appear to those skilled in the art. Accordingly, the above description and accompanying drawings should be taken as specific examples and not in a limiting sense.

Claims

1. A process for recovering at least one rare earth element from at least one material, said process comprising : leaching said at least one material with at least one acid so as to obtain a leachate comprising at least one metal ion, said at least one rare earth element, and a solid, and separating said leachate from said solid; substantially selectively removing said at least one metal ion from said leachate and optionally obtaining a precipitate; and substantially selectively removing said at least one rare earth element from said leachate and/or said precipitate.

2. A process for recovering at least one rare earth element from at least one material, said process comprising : leaching said at least one material with at least one acid so as to obtain a leachate comprising at least one metal ion and said at least one rare earth element, and a solid, and separating said leachate from said solid; and substantially selectively removing at least one member chosen from said at least one rare earth element and said at least one metal ion from said leachate.

3. The process of claim 1, wherein said process comprises: leaching said at least one material with HCI so as to obtain said leachate comprising a first metal ion, a second metal ion and said WO 2012/149642 PCT/CA2012/000419 57 at least one rare earth element, and said solid and separating said leachate from said solid; substantially selectively removing said first metal ion from said leachate, thereby obtaining a composition comprising said second metal ion and said at least one rare earth element; and substantially selectively at least partially removing said second metal ion from said composition, thereby obtaining a liquor comprising said at least one rare earth element.

4. The process of claim 3, wherein said first metal ion is substantially selectively removed from said leachate by substantially selectively precipitating it from said leachate and removing it therefrom by carrying out a solid-liquid separation.

5. The process of claim 3, wherein said first metal ion is at least one aluminum ion and is substantially selectively removed from said leachate by substantially selectively precipitating it under the form of AIC1 3 and removing it therefrom by carrying out a solid-liquid separation.

6. The process of any one of claims 3 to 5, wherein said composition comprises HCI, said second metal ion, and said at least one rare earth element.

7. The process of any one of claims 3 to 5, wherein said composition is an acidic composition that comprises, said second metal ion, and said at least one rare earth element.

8. The process of any one of claims 3 to 7, wherein said second metal ion is at least one iron ion and is substantially selectively removed from said composition by carrying out an hydrolysis so as to convert WO 2012/149642 PCT/CA2012/000419 58 said at least one iron ion into Fe 2 0 3 and removing said precipitated Fe 2 O 3 from said composition by carrying out a solid-liquid separation, thereby obtaining said liquor comprising said at least one rare earth element.

9. The process of claim 8, wherein said at least one iron ion is Fe 3 + and is substantially selectively partially removed from said composition, and wherein said composition is further treated with a reducing agent so as to convert Fe 3 + into Fe 2 + and then, Fe 2 +, under the form of FeC 2 , is removed from said composition by carrying out a solid-liquid separation, thereby obtaining said liquor comprising said at least one rare earth element.

10. The process of any one of claims 3 to 9, wherein said at least one rare earth element is substantially selectively precipitated, extracted and/or isolated from said liquor by means of a liquid-liquid extraction.

11. The process of any one of claims 3 to 10, wherein said at least one rare earth element is extracted from said liquor by means of liquid liquid extraction.

12. The process of any one of claims 3 to 10, wherein said at least one rare earth element is recovered from said liquor by means of liquid liquid extraction.

13. The process of any one of claims 10 to 12, wherein said liquid-liquid extraction is carried out using at least one of di-(2-ethylhexyl) phosphoric acid and mono(2-ethylhexyl)2-ethylhexyl phosphonate.

14. The process of any one of claims 10 to 12, wherein said liquid-liquid extraction is carried out using di-(2-ethylhexyl)phosphoric acid. WO 2012/149642 PCT/CA2012/000419 59

15. The process of any one of claims 10 to 12, wherein said liquid-liquid extraction is carried out using bis(2,4,4 trimethylpentyl)monothiophosphinic acid).

16. The process of any one of claims 10 to 12, wherein said liquid-liquid extraction is carried out using an alkyl phosphate.

17. The process of any one of claims 10 to 12, wherein said liquid-liquid extraction is carried out using tri-butyl phosphate.

18. The process of any one of claims 10 to 12, wherein said liquid-liquid extraction is carried out using octyl phenyl phosphate.

19. The process of any one of claims 10 to 12, wherein said liquid-liquid extraction is carried out using 2-ethylhexylphosphonic acid mono-2 ethylhexyl ester and toluene.

20. The process of any one of claims 10 to 12, wherein said liquor comprises said at least one rare earth element under the form of a chloride, and wherein said liquor is reacted with an extracting agent in order to substantially selectively extract gallium therefrom, thereby obtaining a Ga-free solution and an extracted gallium solution, and separating said solutions from one another.

21. The process of claim 20, wherein said gallium is said liquor is under the form of GaCl 3 .

22. The process of claim 20 or 21, wherein said extracting agent is octyl phenyl phosphate or 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester and toluene.

23. The process of claim 20 or 21, wherein said extracting agent is tri butyl phosphate. WO 2012/149642 PCT/CA2012/000419 60

24. The process of any one of claims 20 to 23, wherein said extracted GaCl 3 is then precipitated and then converted into Ga 2 03.

25. The process of any one of claims 20 to 24, wherein the Ga-free solution is then reacted with another an extracting agent in order to substantially selectively extract cerium therefrom, thereby obtaining a Ce-free solution and an extracted cerium solution, and separating said solutions from one another.

26. The process of claim 25, wherein said cerium in said Ga-free solution is under the form of CeCl 3 .

27. The process of claim 25 or 26, wherein said another extracting agent is tri-butyl phosphate, di-isoamylmethyl phosphonate, di-(2-ethylhexyl) phosphoric acid, or 7-(4-ethyl-1-methyloctyl)-8-hydroxyquinoline.

28. The process of any one of claims 25 to 27, further comprising converting said extracted cerium into CeO 2 .

29. The process of any one of claims 25 to 28, further comprising reacting the Ce-free solution with a further extracting agent in order to substantially selectively extract scandium therefrom, thereby obtaining a Sc-free solution and an extracted scandium solution, and separating said solutions from one another.

30. The process of claim 29, wherein said scandium in said Ce-free solution is under the form of ScCl 3 .

31. The process of claim 29 or 30, wherein said further extracting agent is di-(2-ethylhexyl) phosphoric acid or di-(2-ethylhexyl) phosphinic acid.

32. The process of any one of claims 29 to 31, further comprising converting said extracted scandium into Sc 2 0 3 . WO 2012/149642 PCT/CA2012/000419 61

33. The process of claim 32, wherein said extracted scandium is converted into Sc 2 0 3 by means of NaOH.

34. The process of any one of claims 29 to 33, further comprising reacting the Sc-free solution with still a further extracting agent in order to substantially selectively extract samarium, europium or a mixture thereof, thereby obtaining a Sm-free solution and/or Eu-free solution and extracted samarium and/or europium solution, and separating said solutions from one another.

35. The process of claim 34, wherein said still a further extracting agent is chosen from bis(2,4,4-trimethylpentyl) phosphinic acid and di-(2 ethylhexyl) phosphoric acid.

36. The process of claim 34 or 35, further comprising reacting the Sm-free solution and/or Eu-free solution with still another extracting agent in order to substantially selectively extract gadolinium, thereby obtaining a Gd-free solution and an extracted gadolinium solution, and separating said solutions from one another.

37. The process of claim 36, wherein said still another extracting agent is 8-hydroxyquinoline.

38. The process of claim 36 or 37, further comprising reacting the Gd-free solution with yet another extracting agent in order to substantially selectively extract yttrium, thereby obtaining a Y-free solution and an extracted yttrium solution, and separating said solutions from one another.

39. The process of claim 38, wherein said yet another extracting agent is (2-ethylhexyl)phosphonic acid. WO 2012/149642 PCT/CA2012/000419 62

40. The process of claim 38, wherein said yet another extracting agent is di-(2-ethylhexyl)phosphonic acid.

41. The process any one of claims 38 to 40, further comprising reacting the Y-free solution with still yet another extracting agent in order to substantially selectively extract dysprosium and/or erbium, thereby obtaining a Dy-free solution and/or an Er-free solution and an extracted dysprosium and/or erbium solution, and separating said solutions from one another.

42. The process of any one of claims 3 to 9, wherein said liquor is reacted with a first extracting agent in order to substantially selectively extract gallium therefrom, thereby obtaining a Ga-free solution and an extracted gallium solution, and separating said solutions from one another.

43. The process of claim 42, wherein said gallium in said liquor is under the form of GaCl 3 .

44. The process of claim 42 or 43, wherein said first extracting agent is tri butyl phosphate.

45. The process of claim 42 or 43, wherein said first extracting agent is tri butyl phosphate in kerosene.

46. The process of any one of claims 42 to 45, wherein said Ga-free solution is reacted with a precipitating agent for precipitating at least one rare earth element present in said Ga-free solution, thereby obtaining a precipitate containing said at least one rare earth element and recovering said precipitate via a solid-liquid separation. WO 2012/149642 PCT/CA2012/000419 63

47. The process of claim 46, further comprising leaching said precipitate with at last one acid so as to obtain a leach solution comprising said at least one rare earth element.

48. The process of claim 47, wherein said acid is HCI.

49. The process of any one of claims 46 to 48, wherein said leach solution is reacted with a second extracting agent so as to substantially selectively extract a first group of rare earth elements, thereby obtaining a solution comprising said extracted rare earth elements of said first group and a rafinate comprising a second group of rare earth elements, and separating said solution from said rafinate.

50. The process of claim 49, wherein said first group comprises yttrium and scandium.

51. The process of claim 49 or 50, wherein said second group comprises cerium, neodynium, europium and praseodymium.

52. The process of any one of claims 49 to 51, wherein said second extracting agent is chosen from di-(2-ethylhexyl)phosphoric acid and 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester.

53. The process of any one of claims 49 to 52, further comprising reacting said solution comprising said extracted rare earth elements of said first group with HCI at least once so as to remove impurities therefrom.

54. The process of any one of claims 49 to 53, further comprising stripping said solution comprising said extracted rare earth elements of said first group with an acid so as to obtain a first group strip liquor.

55. The process of claim 54, wherein said acid is HCl. WO 2012/149642 PCT/CA2012/000419 64

56. The process of claim 54 or 55, further comprising repeating at least once said extraction with said second extracting agent.

57. The process of claim 54, 55 or 56, wherein said first group strip liquor is reacted with a third extracting agent so as to substantially selectively extracting at least one of scandium, erbium and dysprosium from said first group strip liquor, thereby obtaining a solution comprising said extracted at least one of scandium, erbium and dysprosium, and an yttrium raffinate, and separating said solution from said raffinate.

58. The process of claim 57, wherein said third extracting agent is tri-butyl phosphate.

59. The process of claim 57 or 58, further comprising stripping said solution comprising said extracted at least one of scandium, erbium and dysprosium solution with an acid so as to obtain another first group strip liquor.

60. The process of claim 59, wherein said acid is HCI.

61. The process of claim 59 or 60, wherein said another first group strip liquor is reacted with a fourth extracting agent so as to substantially selectively extracting erbium and dysprosium from said another first group strip liquor, thereby obtaining a solution comprising said extracted erbium and dysprosium, and a scandium raffinate, and separating said solution from said raffinate.

62. The process of claim 56 or 57, wherein said another first group strip liquor is reacted with a fourth extracting agent so as to substantially selectively extracting scandium from said another first group strip liquor, thereby obtaining a solution comprising said extracted WO 2012/149642 PCT/CA2012/000419 65 scandium, and raffinate comprising erbium dand dysprosium, and separating said solution from said raffinate.

63. The process of any one of claims 3 to 12, wherein said at least one rare earth element is substantially selectively precipitated, extracted and/or isolated by means of an adsorption on activated charcoal optionally modified with tributyl phosphate or on a polyurethane polyether foam (PUF).

64. The process of claim 1 or 2, wherein said at least one rare earth element is substantially selectively removed by means of a liquid liquid extraction.

65. The process of claim 64, wherein said liquid-liquid extraction is carried out by using an extracting agent.

66. The process of claim 65, wherein said extracting agent is chosen from di-(2-ethylhexyl) phosphoric acid, mono(2-ethylhexyl)2-ethylhexyl phosphonate, bis(2,4,4-trimethylpentyl)monothiophosphinic acid), octyl phenyl phosphate (OPAP), 2-ethylhexylphosphonic acid mono-2 ethylhexyl ester, tributyl phosphate, di-isoamylmethyl phosphonate, 7 (4-ethyl-1 -methyloctyl)-8-hydroxyquinoline, di-(2-ethylhexyl) phosphinic acid, bis(2,4,4-trimethylpentyl) phosphinic acid, 8 hydroxyquinoline, and (2-ethylhexyl)phosphonic acid.

67. The process of claim 65, wherein said extracting agent is chosen from diethylenetriamine-penthaacetic acid, ethylenediaminetetraacetic, 1,4,7,1 0-tetraazacyclododecane-1,4,7,1 0-tetraacetic acid, and bis(2,4,4-trimethylpentyl)monothiophosphinic acid.

68. The process of claim 64 to 67, wherein said at least one rare earth element is chosen from scandium, gallium, yttrium, lanthanum, WO 2012/149642 PCT/CA2012/000419 66 cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, dysprosium, erbium, and ytterbium.

69. The process of claim 64 to 67, wherein said at least one rare earth element is chosen from scandium, gallium, yttrium, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium and dysprosium.

70. The process of claim 64 to 67, wherein said at least one rare earth element is chosen from scandium, gallium, yttrium and cerium.

71. The process of claim 64 to 67, wherein said at least one rare earth element is chosen from scandium, gallium and yttrium.

72. The process of claim 2, wherein said at least one metal ion comprises a first metal ion and a second metal ion and said process comprises selectively precipitating at least two members chosen from said at least one rare earth element that is in the form of ions, said second metal ion and said first metal ion.

73. The process of claim 72, wherein each of said members is precipitated separately.

74. The process of claim 72, wherein said at least two members are precipitated together.

75. The process of any one of claims 1 to 12, wherein said at least one rare element is chosen from scandium, gallium, yttrium and cerium.

76. The process of any one of claims 1 to 12, wherein said at least one rare element is cerium. WO 2012/149642 PCT/CA2012/000419 67

77. The process of any one of claims 1 to 12, wherein said at least one rare element is gallium.

78. The process of any one of claims 1 to 10, wherein said at least one rare element is scandium.

79. The process of claim 78, wherein said scandium is precipitated in the form of Sc(OH) 3 , ScCl 3 , ScF 3 , and/or [ScFe] 3 - or hydrates thereof.

80. The process of claim 78, wherein said scandium is precipitated in the form of Sc(OH) 3 or hydrates thereof.

81. The process of claim 79 or 80, wherein said scandium is precipitated at a pH of about 7 to about 9.

82. The process of claim 79 or 80, wherein said scandium is precipitated at a pH of about 7 to about 8.

83. The process of claim 1, wherein said process comprises leaching said at least one material with HCI so as to obtain said leachate comprising a first metal ion, a second metal ion and said at least one rare earth element, and said solid and separating said leachate from said solid; substantially selectively removing said second metal ion from said leachate, thereby obtaining a composition comprising a first metal ion and said at least one rare earth element; and substantially selectively at least partially removing said first metal ion from said composition, thereby obtaining a liquor comprising said at least one rare earth element. WO 2012/149642 PCT/CA2012/000419 68

84. The process of any one of claims 1 to 12, wherein said process comprises leaching said at least one material with HCI so as to obtain said leachate comprising a first metal ion, a second metal ion, and said at least one rare earth element, and said solid and separating said leachate from said solid; substantially selectively removing said second metal ion from said leachate, thereby obtaining a composition comprising said first metal ion, and said at least one rare earth element; and substantially selectively at least partially removing said first metal ion from said composition, thereby obtaining a liquor comprising said at least one rare earth element.

85. The process of claim 83 or 84, wherein said second metal ion comprises at least one iron ion that is substantially selectively precipitated in basic conditions in which the pH is of at least 10.

86. The process of claim 85, wherein said pH is at least 11.

87. The process of claim 85, wherein said pH is at least 12.

88. The process of claim 85, wherein said pH is about 10.8 to about 11.2.

89. The process of claim 85, wherein said pH is about 11.5 to about 12.5.

90. The process of claim 85, wherein said pH is comprised between 11 and 12.

91. The process of claim 83 or 84, wherein at least a portion of said second metal ion is precipitated at a pH of about 3 to about 4. WO 2012/149642 PCT/CA2012/000419 69

92. The process of claim 83 or 84, wherein at least a portion of said second metal ion is precipitated at a pH of about 3.0 to about 3.5.

93. The process of claim 83 or 84, wherein at least a portion of said second metal ion is precipitated at a pH of about 3.5 to about 4.0.

94. The process of claim 83 or 84, wherein at least a portion of said second metal ion is precipitated at a pH of about 5 to about 6.

95. The process of claim 83 or 84, wherein at least a portion of said second metal ion is precipitated at a pH of about 5.0 to about 5.5.

96. The process of claim 83 or 84, wherein said leaching is carried out at a pH of about 0.5 to about 2.5, then said second metal ion is precipitated at a pH of at least about 9.5, then said first metal ion is precipitated at a pH of about 8 to about 9, and then at least one scandium ion is precipitated at a pH of about 7 to about 8.

97. The process of claim 83 or 84, wherein said leaching is carried out at a pH of about 0.5 to about 1.5, then said second metal ion is precipitated at a pH of at least about 10.5, then said first metal ion is precipitated at a pH of about 8 to about 9, and then at least one scandium ion is precipitated at a pH of about 7 to about 8.

98. The process of claim 83 or 84, wherein said leaching is carried out at a pH of about 0.5 to about 1.5, then said second metal ion is precipitated at a pH of at least about 11, then said first metal ion is precipitated at a pH of about 8 to about 9, and then at least one scandium ion is precipitated at a pH of about 7 to about 8.

99. The process of any one of claims 85 to 98, wherein said first metal ion is at least one aluminum ion and said second metal ion is at least one iron ion. WO 2012/149642 PCT/CA2012/000419 70

100. The process of any one of claims 78 to 82 and 96 to 98, wherein said scandium is precipitated from a solution generated during said process or wherein said scandium is precipitated from a by-product generated during said process.

101. The process of claim 100, wherein said scandium is precipitated using HNO 3 .

102. The process of claim 1 or 2, wherein said at least one rare earth element is substantially selectively precipitated, extracted and/or isolated by at least one technique chosen from ion exchange resin, extraction by means of solvent(s) and adsorption.

103. The process of claim 1 or 2, wherein said at least one rare earth element is substantially selectively precipitated, extracted and/or isolated by means of an ion exchange resin.

104. The process of claim 1 or 2, wherein said at least one rare earth element is substantially selectively precipitated, extracted and/or isolated by means of a liquid-liquid extraction.

105. The process of claim 1 or 2, wherein said at least one rare earth element is substantially selectively precipitated, extracted and/or isolated by means of an electrowinning process.

106. The process of claim 83 or 84, wherein said leaching is carried out at a pH of about 0.5 to about 2.5, then said second metal ion is precipitated at a pH of at least about 9.5, then said first metal ion is precipitated at a pH of about 8 to about 9, and then and then said at least one rare earth element is substantially selectively extracted.

107. The process of claim 83 or 84, wherein said leaching is carried out at a pH of about 0.5 to about 1.5, then said second metal ion is WO 2012/149642 PCT/CA2012/000419 71 precipitated at a pH of at least about 10.5, then said first metal ion is precipitated at a pH of about 8 to about 9, and then said at least one rare earth element is substantially selectively extracted.

108. The process of claim 83 or 84, wherein said leaching is carried out at a pH of about 0.5 to about 1.5, then said second metal ion is precipitated at a pH of at least about 11, then said first metal ion is precipitated at a pH of about 8 to about 9, and then said at least one rare earth element is substantially selectively extracted.

109. The process of any one of claims 1 to 108, wherein said leaching is carried out with HCl under a pressure of about 5 KPag to about 850 KPag.

110. The process of any one of claims 1 to 108, wherein said leaching is carried out with HCI under a pressure of about 50 KPag to about 800 KPag.

111. The process of any one of claims 1 to 108, wherein said leaching is carried out with HCI under a pressure of about 100 KPag to about 750 KPag.

112. The process of any one of claims 1 to 108, wherein said leaching is carried out with HCI under a pressure of about 150 KPag to about 700 KPag.

113. The process of any one of claims 1 to 108, wherein said leaching is carried out with HCI under a pressure of about 200 KPag to about 600 KPag.

114. The process of any one of claims 1 to 108, wherein said leaching is carried out with HCI under a pressure of about 250 KPag to about 500 KPag. WO 2012/149642 PCT/CA2012/000419 72

115. The process of any one of claims 1 to 108, wherein said at least one material is leached with HCI at a temperature of at least 80 *C.

116. The process of any one of claims 1 to 108, wherein said at least one material is leached with HCI at a temperature of at least 90 *C.

117. The process of any one of claims 1 to 108, wherein said at least one material is leached with HCI at a temperature of at least 120 *C.

118. The process of any one of claims 1 to 108, wherein said at least one material is leached with HCI at a temperature of at least 140 0C.

119. The process of any one of claims 1 to 108, wherein said at least one material is leached with HCI at a temperature of about 100 0C to about 110 *C.

120. The process of any one of claims 1 to 108, wherein said at least one material is leached with HCI at a temperature of about 140 0C to about 175 *C.

121. The process of any one of claims 1 to 120, wherein said acid is HCI having a concentration of about 6 M.

122. The process of any one of claims 1 to 120, wherein said acid is HCI having a concentration of about 18 to about 32 wt%.

123. The process of any one of claims 1 to 122, wherein the at least one material / acid ratio is about 1 / 10 in weight by volume.

124. The process of claim 1 or 2, further comprising at least one of at least partially removing said at least one metal ion from said leachate by substantially complexing said at least one metal ion with an extracting agent; WO 2012/149642 PCT/CA2012/000419 73 selectively precipitating said at least one metal ion; selectively precipitating said at least one metal ion; and at least partially removing said at least one metal ion from said leachate by substantially complexing said at least one aluminum ion with another extracting agent.

125. The process of claim 1 or 2, wherein said process comprises: leaching said at least one material with HCI so as to obtain a leachate comprising a first metal ion and a second metal ion and a solid residue, and separating said leachate from said solid residue; at least partially removing said second metal ion from said leachate by substantially selectively precipitating said second metal ion by reacting said leachate with a base so as to obtain an aqueous composition rich in said first metal ion comprising said at least one rare element and a precipitate, and removing said precipitate from said composition; purifying said aqueous composition by substantially selectively precipitating said first metal ion, thereby obtaining another composition comprising said at least one rare element and another precipitate, removing said precipitate from said composition; and substantially selectively extracting said at least one rare element from said another composition.

126. The process of claim 1 or 2, wherein said process comprises: WO 2012/149642 PCT/CA2012/000419 74 leaching said at least one material with HCI so as to obtain a leachate comprising a first metal ion and a second metal ion and a solid residue, and separating said leachate from said solid residue, at least partially removing said second metal ion from said leachate by substantially selectively precipitating said second metal ion by reacting said leachate with a base so as to obtain an aqueous composition rich in said first metal ion comprising said at least one rare element and a precipitate, and removing said precipitate from said composition; substantially selectively extracting said first metal ion from said aqueous composition by means of a hollow fiber membrane, or by a liquid-liquid extraction, and removing said extracted first metal ion, thereby obtaining an aqueous composition depleted in said first metal ion and comprising said at least one rare element; and substantially selectively extracting said at least one rare element from said aqueous composition depleted in said first metal ion.

127. The process of claim 1 or 2, wherein said process comprises: leaching said at least one material with HCI so as to obtain a leachate comprising a first metal ion and a second metal ion and a solid residue, and separating said leachate from said solid residue; at least partially removing said second metal ion from said leachate by substantially selectively complexing said second metal ion with an extracting agent so as to obtain an aqueous WO 2012/149642 PCT/CA2012/000419 75 composition rich in said first metal ion and comprising said at least one rare earth element; purifying said aqueous composition by substantially selectively precipitating said first metal ion, thereby obtaining another composition comprising said at least one rare element and another precipitate, removing said precipitate from said composition; and substantially selectively extracting said at least one rare element from said another composition.

128. The process of claim 1 or 2, wherein said process comprises: leaching said at least one material with HCI so as to obtain a leachate and a solid residue, and separating said leachate from said solid residue; at least partially removing said second metal ion from said leachate by substantially selectively complexing said second metal ion with an extracting agent so as to obtain an aqueous composition rich in said first metal ion and comprising said at least one rare earth element; substantially selectively extracting said first metal ion from said aqueous composition rich in said first metal ion by means of a hollow fiber membrane, or by a liquid-liquid extraction, and removing said extracted first metal ion, thereby obtaining an aqueous composition depleted in said first metal ion and comprising said at least one rare element; and substantially selectively extracting said at least one rare element from said aqueous composition depleted from said first metal ion. WO 2012/149642 PCT/CA2012/000419 76

129. The process of claim 1 or 2, wherein said process comprises: leaching said at least one material with HCI so as to obtain a leachate and a solid residue, and separating said leachate from said solid residue; at least partially removing said first metal ion from said leachate by substantially selectively precipitating said first metal ion so as to obtain an aqueous composition rich in said second metal ion and comprising said at least one rare element and a precipitate, and removing said precipitate from said composition; substantially selectively precipitating said second metal ion from said aqueous composition rich in said second metal ion, and removing said precipitate therefrom, thereby obtaining an aqueous composition depleted in said second metal ion and comprising said at least one rare element; and substantially selectively extracting said at least one rare element from aqueous composition depleted in said second metal ion.

130. The process of claim 129, wherein said first metal ion comprises at least one aluminum ion that is precipitated under the form of AICl 3 in a crystallizer by sparging gaseous HCI.

131. The process of claim 129, wherein said second metal ion comprises at least one iron ion that is precipitated under the form of Fe 2 O 3 by means of an hydrolysis.

132. The process of claim 125, wherein said first metal ion comprises at least one aluminum ion and wherein said aqueous composition rich in said first metal ion is purified by complexing said at least one aluminum ion with an extracting agent so as to obtain a complex, WO 2012/149642 PCT/CA2012/000419 77 separating said complex form said composition and precipitating said at least one aluminum ion.

133. The process of claim 132, wherein said extracting agent is bis(2,4,4 trimethylpentyl) phosphinic acid.

134. The process of claim 126 or 127, wherein said first metal ion comprises at least one aluminum ion and wherein said aqueous composition rich in said first metal ion is purified by complexing impurities contained in said aqueous composition with an extracting agent, at least partially removing said complexed impurities from said composition and precipitating said at least one aluminum ion.

135. The process of claim 134, wherein said extracting agent is chosen from di-2-ethylhexyl phosphoric acid (HDEHP), bis(2,4,4 trimethylpentyl) phosphinic acid and 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester.

136. The process of any one of claims 125 to 129, wherein said first metal ion comprises at least one aluminum ion and wherein said second metal ion comprises at least one iron ion.

137. The process of claim 1 or 2, wherein said leaching is carried out with an acid chosen from HCI, H 2 SO 4 , HNO 3 and mixtures thereof.

138. The process of claim 8, wherein after said removal of said precipitated Fe 2 0 3 , said liquor containing said at least one rare earth element is recirculated back for being further concentrated by being used in precipitating the at least one aluminum ion.

139. The process of claim 8, wherein after said removal of said precipitated Fe 2 0 3 , said liquor containing said at least one rare earth element is WO 2012/149642 PCT/CA2012/000419 78 recirculated back for being further concentrated by being used in precipitating the at least one aluminum ion under the form of AICl 3 .

140. The process of any one of claims 1 to 8, 83 to 89, 97 to 99, 106 to 108, 125, 126, 137 and 138 wherein said second metal ion comprises at least one iron ion that is precipitated under the form of Fe(OH) 3 , Fe(OH) 2 , geotite, hematite and jarosite, hydrates thereof or mixtures thereof.

141. The process of any one of claims 83 to 89, 97 to 99, 106 to 108, 125 and 127, wherein said first metal ion comprises at least one aluminum ion that is precipitated under the form of AI(OH) 3 or hydrates thereof.

142. The process of any one of claims 1 to 141, wherein said at least one material is an aluminum-bearing material.

143. The process of claim 142, wherein said aluminum-bearing material is chosen from clays.

144. The process of a claim 142, wherein said aluminum-bearing material is chosen from argillite, mudstone, beryl, cryolite, garnet, spinel, bauxite and mixtures thereof.

145. The process of claim 142, wherein said aluminum-bearing material is argillite.

146. The process of claim 142, wherein said aluminum-bearing material is red mud.

147. The process of any one of claims 1 to 141, wherein said at least one material is a nickel-bearing ore. WO 2012/149642 PCT/CA2012/000419 79

148. The process of any one of claims 1 to 141, wherein said at least one material is a nickel-bearing ore that is niccolite, kamacite, taenite, limonite, garnierite, laterite or pentlandite.

149. The process of any one of claims 1 to 141, wherein said at least one material is a zinc-bearing ore.

150. The process of any one of claims 1 to 141, wherein said at least one material is a zinc-bearing ore that is chosen from smithsonite, warikahnite, sphalerite, and mixtures thereof.

151. The process of any one of claims 1 to 141, wherein said at least one material is a copper-bearing ore.

152. The process of any one of claims 1 to 141, wherein said at least one material is a copper-bearing ore that is chosen from copper-bearing oxide ores.

153. The process of any one of claims 1 to 141, wherein said at least one material is a copper-bearing ore that is chosen from chalcopyrite, chalcocite, covellite, bornite, tetrahedrite, malachite, azurite, cuprite, chrysocolla, and mixtures thereof.

154. The process of any one of claims 1 to 141, wherein said at least one material is a titanium-bearing ore.

155. The process of any one of claims 1 to 141, wherein said at least one material is a titanium-bearing ore that is chosen from ecandrewsite, geikielite, pyrophanite, ilmenite, and mixtures thereof.